What I think will happen is that there will be a backlash against these kinds of films--a readjustment of some kind that will kill off the superhero films or at least cause them to be scaled back in a dramatic fashion.
They used to make a lot of Westerns in Hollywood, and then Sputnik happened, or so they say. There are no films for adults anymore, so what will happen if one or two of these superhero films tanks and goes down in flames next to a billion dollar hit made for a fraction of the cost?
Rest assured, I'm just trolling. Marvel's announcement proves one thing and one thing only--the teenaged boys of China will have films to watch for the next six years and these films will be made specifically for them and for no one else.
If there is a backlash, it will be short-lived because the foreign market for films is where the money is. And Hollywood chases money better than any other industry.