Originality in Hollywood, what's that?
The key thing to remember about the tentpole type of Hollywood movie is that they are made for the global market, which requires them to be cartoonish and simplified. You can't really have any point of view when you are trying to appeal to everyone, and if a lot of your audience doesn't even understand English and is reading subtitles, it's better to veer more towards action and away from dialogue. Of course it's hard to convey any degree of complexity without dialogue, so that makes movies even more cartoonish. How can any filmmaker get a vision across under these conditions?
Hollywood also continues to make Oscar-bait movies, and those don't need to have global appeal, since the goal is to gain prestige for the studio rather than just make as much money as possible, so they tend to deal with more complex ideas and have a point of view.
Looking at the top 5 movies in 2012 for international BO vs the Oscar contenders is enlightening. The % are domestic vs international BO.
1. Marvel's The Avengers - 41%/59%
2. The Dark Knight Rises - 42%/58%
3. The Hunger Games - 59%/41%
4. Skyfall - 27%/73%
5. The Hobbit: An Unexpected Journey - 31%/69%
Now look at the Hollywood-made Oscar contenders (in no particular order)
Lincoln - 75%/25%
Argo - 62%/38%
Zero Dark Thirty - 87%/13%
Life of Pi - 19%/81%
Django Unchained - 43%/57%
Beasts of the Southern Wild - 100%/0% (not even released internationally I guess?)
Les MisÚrables - 39%/61%
Silver Linings Playbook - 71%/29%
In general, this group has a stronger domestic skew and also reflect their filmmakers' vision more strongly. (Interestingly, the ones that like the tentpole movies are fantasy based have a stronger global skew.)
The moral of the story is, any filmmaker who wants to present an artistic vision should be doing the type of movie that debuts in the fall, not the summer. And this also explains why JJ Abrams is "ruining" Star Trek