Hollywood is an incestuous, nepotistic enclosed environment. Whether acting, writing or directing, family and friends comprise the majority of the "big deals". Very few outsiders break into that community without working their way up in the studio system or married/friended into it. This issue arises again and again in this forum.
1. It is not being negative but being realistic--writing a blockbuster screenplay as an outsider and making millions is as likely as hitting the lottery. Perhaps in the past, but not so much anymore. Even Bluecat and Nichols winners and finalists are not guaranteed to have their prize-winning screenplays made into films. If you cultivate industry connections, you might be able to get someone to look at your script. What I find over-and-over reading and hearing interviews is that the main sell of a script by non-insiders comes from a face-to-face pitch that arises by happenstance either to a movie executive or sympathetic insider. You need someone higher up on the food chain than a few readers to get that script into an executive's hands. That's where managers and lit agents help. If like Shane Black, you're a UCLA graduate and actor with an agent back in the 1980s, you could probably get someone to read your script. That's the only way Blackisms today would fly and your agent would probably still discourage them.
2. Studios almost completely shun originality. They prefer to buy pre-existing products (novels, comics, television, games, etc.) that they can adapt to the screen. Even movies which we consider classics (Maltese Falcon, Wizard of Oz, Gone with the Wind, etc.) are based on best selling books. Since the studios are now targeting younger audiences, most of the big bucks are invested to cater to them. A poll of people who actually saw Oscar nominated films ("12 Years a Slave", "Gravity", etc.) revealed a very small percentage. While quality comes from smaller independent studios, the bulk of the large investments are in 'junk food' comic adaptations. When you see the long list of A-list actors on some of these DC and Marvel comic films, you see the above the line budget just skyrocketing. It's not that they're not fun to watch, but on the flip side, that's why no one in Hollywood really gives a rat's ass about your script when you send it in. Hollywood has become exceedingly risk-adverse.
3. It is far easier if you write and direct your own work. You can show it in a festival, watch online or go the direct to dvd route. You get instant IMDB creds and if you're lucky and talented, it will get noticed by others who can help you jumpstart your career. Writer/Directors are much more successful in making the leap. Spielberg, Lucas, Bruckheimer, Abrams, Tarantino, etc. all got their breaks not because of their writing but by their directing. Spielberg interned as student helping in television. Lucas' THX won an award and was noticed. Bruckheimer worked with a director and produced ads and films before breaking off. Tarantino's writer/director debut won him attention in part because Harvey Keitel, through his contacts, helped produce and act in it. Again, most successful screenwriters have emerged from partnerships and contact with directors. I want to emphasize the importance of networking.
4. It is not impossible to break into the ranks but it takes dedication. Most people believe if they write a good screenplay it will make them rich and famous. They want a winning lottery ticket. Most of the people who have succeeded have put sweat equity into honing their skills. So, yeah, we can say "Wow, $10 million for his/her screenplay. I wonder what their secret is?" Bottom line, write, work to improve, network, and be willing to work in the field. Sometimes you get lucky and have the ear of the right person. But you can still make your own "luck" if you take responsibility and put in the effort.
