Well, I would imagine that post work has some value, lol. (I'm guessing you haven't seen a lot of my work)
Story is the core of everything, obviously. Everything else in a film should be designed to serve the story. Simultaniously, film, and especially film business/ROI, is a very complex ordeal, that relies on multifaceted strategies to work.
I remember starting out in indie film, and thinking that I could make compelling dramas without the need for much post work. And I could, but not without huge money I didn't have. So many people are fighting for a share of the audience, and viewing decisions are typically based on a single image, maybe a paragraph or trailer if you're lucky.
So let's say you write a drama script of identical quality to "A Few Good Men". Cost is close to zero, and you're already on the way to an Oscar right? Everything is going great so far. So you decide to forgo post altogether, and just tell a good story. Now instead of luring your audience to the product with flashy post, you are doing it the right way, giving them a solid drama worth watching. If you build it, they will come, right?
So you make the film, and with no studio backing you up, you have to make some concessions on actors and sets. Jack Nickolson would be great for the role of the main antagonist, but it costs 22 indie film budgets for him to show up for 2 months of filming, so you go with Twill Jackerson instead, a local postman who once saw a youtube video about acting. Cuba Gooding Jr is also available, at the entire budget of your film just for him. So you hire Dave Phillips, an elementary school teacher who has great line retention, and an infectious sense of humor. After hanging out with Dave a few times, you really like the guy, and you're convinced audiences will like him too.
With your cast in place, it's time to set up some locations. The story you wrote was set on a military base, but that's way out of your price range, but you and a few friends stay up drinking one night and in a flash of genius level inspiration, you realize that on screen, a military base is just some buildings with beds and a few tents here and there. You find surplus military tents and cots online, and you're off to the races. However, half the movie is set in a courtroom, and no one will let you film in a courtroom. Initially confused, you do some research, and find that MGM didn't rent a courtroom either, they built one from scratch, and it cost about as much as the citizens of your town made collectively in the last decade. You do the best you can, but at the end, your characters spend the entire film standing next to some generic surplus tents, and it's really not that exciting or convincing in the film. It turns out that without an airfield full of helicopters, your military base just looks like a salvation army tent set up in a park.
Your crew is made up of some pretty smart people, and they do a good job. Cinematography, color, sound, are all on point, and you talk in the evenings about what a good chance you have, because you're really nailing a lot of stuff you've seen more successful films screw up.
You watch the finished movie, and within 20 minutes, you're sucked in, the story really works, and even though you already know, you watch intently to see what happens next. At the end, everyone is high fiving each other. You did it, you made a film on pure story, and it worked. Now you can simply go and collect your 10 million dollars, next stop Hollywood.
Everyone on your limited crew is really into film and art, and no one cares much about business, so with a limited budget to start, no one bothered to research how much money should be put into marketing (it's 50% of your total budget, ballpark) and you don't do any. The film is so great by the 30 minute mark, that you are pretty sure word of mouth will do the job for you anyway.
Now it's time for the film to be released into the wild and come into contact with the audience. Amazon and other streaming services are telling you that you can just skip the step of having a studio release your film, and now you can go live immediately, without having to split the profits up with a distributor. Considering all your money is gone at this point, it sounds great.
So it's day one, and Shelia Jackson of Talahassee Florida is the first person to see your thumbnail on Amazon. it's 3.99 for the rental, and the movie looks interesting to her based on the blurb, which is all they can fit in the list of 87 new films released that week. But she's in the minority, most people just scan past. She goes to the imdb page, trying to become interested. There's a picture of 2 guys she's never seen before, standing next to a tent. Both of them have a serious look on their faces, like something dramatic is happening. Sadly, it looks cheap and cut rate to her. Still trying to take an interest, she reads the actor links, to see if anyone in the film has ever been in anything else. They haven't. What studio made this, maybe it's from some studio that made something else she liked. No, she's never heard of it. She's lost interest now, and goes back to the list of new films for the week, and there's 22 other movies, starring people she has heard of, made with large budgets, perhaps even a reboot of a movie she liked decades ago. And that's it. 10 million people repeat this same process, and those are the 10 million that didn't just immediately scan past your entry when they didn't recognize the main stars names. None of those people ever got far enough to find out that your actors did an amazing job delivering that courtroom scene starting on minute 29. With no one watching, no one is talking about it. You didn't advertise, so there are no inroads there either. You made a website, but SEO is a nightmare, and no one on your team is that great at it. Even if they were, your underdog story isn't really turning out like it does in the movies. People with 10,000 times your advantage sets are monopolizing the market to a degree that no indie filmmaker could realistically compete with.
Everyone related to you and all the actors rents it to help out, and you're kind of hoping that it gets the ball rolling, but it's like throwing a cup of water into the ocean to see if the tide will rise.
So next movie, you use a lot of sfx, and it looks amazing on a purely superficial level, and that single publicity image that people base their decision on has a lot more impact. The plot isn't as good, but this time a few hundred thousand people click on the thumbnail, and they do get to the 30 minute mark, though only because they're out 4 bucks already, and the sfx is decent. There's a genuinely funny moment or two in there, and since the effects hooked them in long enough to get them past the huge negative that is a cover shot of two unknown actors arguing, they do talk a bit about it on the net. There are a few legitimate reviews, and maybe you break even.
So this is really about marketing. A great script without famous actors just fails, at least stateside. SFX is a way for filmmakers to increase production values in a market where they are desperately needed for success. Sadly, the viz work is second rate just like the actors, and every week there are many first rate choices competing. So either way, people with talent and no money are all doomed.
You just had 3 seconds to capture that viewer, and there were almost 90 films on that list they were scrolling through. You thought they would be impressed with your creativity, or skill, or work, but every single time, they opted for something with a higher budget.
You lost all your money. Your friends that used SFX lost all their money. The ones who were kind of rich to begin with go on the "emperor's new clothes" tour. Getting sauced in hotel rooms and attending "important meetings" with other indie directors in the "Jeff Holloway Memorial Ballroom". No one knows who Jeff Holloway was, but you're all just excited to be in Miami, at a real film convention. Everyone in the room lost all their money. There are some pretty good parties thrown by people in severe denial, and you have a good time. The people who really needed a break the worst, nose to the grindstone for 3 years with no funding to start with, they just go home and sit alone, their finances exhausted by trying to play roulette at the high stakes table for one night of their lives.
A few months later, Amazon sends you a check. it's 4,381 dollars, for your cut of the streaming rentals. That's to split between the team. You're out 71 grand from the film.
Why do people use sfx? To try and even the odds a bit in a market where they can be beaten in seconds with a wave of a wallet from some guy with a 30 billion dollar bankroll, and he's not even spending his own money. Does it work? Sometimes, sort of, not really, not often. It just works marginally better than making your POS a photo of two strangers on a blank background.
Try to imagine a poker table, but instead of poker, the game is that whoever has the most money wins automatically. The same people win over and over, and it's an extreme exception to the rules when a person that doesn't come from wealth wins.
My advice to indie filmmakers, is to niche down into an area of lesser competition, establish and income stream there, and then leverage that success into something bigger in stages. Think of creativity and intelligence as a force multiplier for resources (or vice versa) and then take a tactic based on that math, rather than trying to demonstrate skill until money arrives.
You know why Jackass is the most successful indie film of all time? Because they had a hook that didn't require any quality to start, then made money on that basic thing, and were able to stage up over time. Personally, I hate Jackass, and consider it extremely stupid, but they were humble enough to make a buck or two before trying to take on the international market singlehandedly.
Get the engine running, and then try to race. As far as SFX ruining movies that would have otherwise been good, I don't think that happens much. Usually, and I think this is what you're saying, people don't have much of a plot, and try to substitute sfx for a plot. That does not work. If you have a good product to start with, good sfx can enhance it a lot.
As a post/viz mercenary myself, I could talk all day about the role of post in film, but I'll keep it down to one paragraph here. The biggest mistake I see filmmakers make regarding post is that they think it should be up front and obvious, or it's not needed. Smart directors and viz people know that the very apex of the skill is only achieved invisibly, when the audience never realizes that there were any sfx at all. Many high end directors know this, but indie filmmakers typically don't. Sky replacement on a boring day, adding trees to balance a shot, making traffic look busy when you couldn't afford to hire 75 drivers and shut down 3 city blocks. These are more refined approaches to adding PV via viz. Vis should enhance and compliment a story, it's not a replacement as many seem to think.
Personally, I'm just making a cartoon for young people to enjoy. They aren't as jaded as adult viewers, and unlike mature drama, which I would also like to make, I can come up with 500 case studies where people made serious profits. Once you have money coming in, the game changes a lot, and a smart director can snowball small wins into a fighting chance.
I write a lot on here, it's a break from demanding post work, and It keeps the rust off when it comes to just knocking out a few pages of text on demand. Just explaining why I wrote 2 pages here instead of the customary internet response "Yeah, special effects sucks"
Here's an example of what I'm talking about, I found it in 3 minutes. This is a small film, but it's published by a known studio. This is the lead trailer, the official channel one. It has 200k views, less than most videos about how to make a waffle. every other copy of the trailer is sitting at about 100 hits. Even with some studio support, and a few million in budget, these guys are going to loose their shirts on this movie. It has both drama and SFX, but still failed horribly. It's an interesting case study in terms of wrapping one's head around exactly how much resistance indie filmmakers face in the current market.
Here's a music video from the movie, it actually has 3x the views that the actual movie got, despite being terrible