I agree with what you say however I think there is more to it than just audience homogeneity...what I mean by that is Hollywood movies are very well received overseas but the target audience are certainly not white or Americans. Could it be part of the 'colonial' mentality? I think so but then again I'm no social scientist.
Another part could be due to 'attractiveness'.. I think it is safe to assume that there many times more Asian men and women who are more partial to the likes of Brad Pitt, Tom Cruise, Angelina Jolie etc than say 'white' American men and women who thinks the same for the likes of Jackie Chan, Jet Li or Lucy Liu etc.
Well, it also have to do with the fact that Hollywood is the only one that can afford to spend hundreds of millions of dollars on a movies. That means the world's best technology are at their disposal, and so are some of the world's top directors, script writers etc...
Also the fact that American culture itself is extremely popular in the world, and Hollywood is a important expression of American culture.
Did you know that by quantity wise, India is the nation that makes the most amount of movies per year? But their production quality, script writing does not even come close.
This is something China need to work on, they may have very powerful economic influence already, but their cultural influence sucks very badly right now. I would say, even Korean and Japanese culture by itself is more influential than Chinese cultures worldwide.