You give Hollywood both too much and too little credit. Although the financing of movies is pretty much down to five companies (actually virtually ALL popular culture is created by those five companies) beneath the surface it's chaotic. Writers, directors, actors etc. fighting for projects, money, etc. Scripts being re-written at the las minute. Actors and directors being replace. For instance, the movie Pretty Woman was originally written as a very dark social commentary and then changed as they were shooting it to romantic comedy. So who knows how Starship Troopers, by that most American of Scifi writers, started out or how it was seen by a dutch guy who directed both action adventure and social commentary.
Who even knows how they edited it or re-cut it once it was shot? Body Heat, for instance, was re-cut (brilliantly) at the last minute with something like 20 minutes edited out of it. If you look closely, you can see conversations between two characters taking place while they are in different locations.
That said, there is no "Hollywood" as you think of it. No monolithic organization with a single vision -- at least not a vision that extends beyond keeping their jobs and making money. I've met a bunch of Hollywood producers, directors, etc. over the years through odd twists of fate and I can state without hesitation that they are the most frightened people you would ever hope to meet. They are in a highly competitive field that offers big money, but only if you "guess" right almost every time. It's pretty much like having a high paying job where the boss tells you to go into a casino and make three very large bets. If you bet right, then you get to keep your job. If you guess wrong, then you're fired.
Pretty damn good post.