Tom Petty wouldn't get past the initial audition on American Idol, but that doesn't mean he wouldn't be successful as a musician - and also doesn't mean the American Idol judges would be wrong to dismiss him if he doesn't fit the criteria they've established for what they're looking for.
...Again, I would agree with you if American Idol represented the full force of the music industry. It doesn't! It's just a tiny fraction of what a musician can access to make it in the music industry. The Screenwriting equivalent might be "The PAGE Fellowship" or some other high-profile contest.
The music industry is made up of Universal Music Group, Sony Music Entertainment, Inc., Warner Music Group, and EMI Music Group. Out of these giants you get the famous record labels like RCA, Columbia Records, Atlantic Records, Etc. Etc..
The movie industry is made up of Warner Bros., Disney, NBC Universal (Universal Pictures), Columbia TriStar (Columbia Pictures), and FOX Entertainment (20th Century and Paramount), etc.
In both the music AND the movie industry you have a WIDE VARIETY of options for you to sell your art. A Tom Petty could sell his particular talent just like Trent Resnor, Marilyn Manson and Michael Buble could sell their own particular "style".
However, ....try writing your OWN FRICKIN' STYLE of movie script and you're drummed out of the industry at page 121 (or god forbid you have your address on the title page). Suddenly all the shit you regularly see showing up on the movie screens around the world (lots of exposition, "On-the-Nose" dialogue, flat characters, butt-numbingly long films) is NOT ALLOWED to be accessed by the Spec Script writer.
It's not "American Idol" ....It's a sub-culture of "fear" the permeates the Spec Script community to where any new talent is completely scared shitless to do ANYTHING that may be considered "breaking the rules" that someone established long, long ago.
It's a "Catch 22". People want crazy, off-the-wall movies that break the rules and excite people. They want NEW talent to write these films ...So they then demand that the "new talents" all subscribe to a clean, precise, cookie-cutter mindset and not do anything that may "raise eyebrows" or "Flag your script". Then if some script with all the crazy "rule breaking" shit we love miraculously manages to slide through all of the "Safe Script Filters" and makes it to the silver screen ...we celebrate the script writer as a god.
The best example I can provide is "Bodybuilding"
I've watched bodybuilding instructional videos from all kinds of famous body builders. They have all kinds of "rules and regulations" regarding what you are supposed to do to build muscle. They show how you are supposed to lift slowly and carefully, (2 seconds up - 5 seconds down), proper stance, proper diet, you name it. If you want to get big ...that's how you do it! THEN I'll see a video of these same bodybuilders eating a Whopper for lunch and in the Gym they are breaking every single rule that they've pushed so hard in the industry. They break the rules THEY established themselves.
I remember asking in a forum once, "So why does he say you are supposed to do lift one way, then in the gym he does it the complete opposite?" and the response I get is, "When you get to be as big as he is, then you can break the rules".
I get the same responses in the movie industry. Nobody seems to grasp the "Catch 22" in any of this.
-Birdman.