Wow, that would be really brutal. Disney in particular (which dominates the box office) relies enormously on the Chinese market. They already make a lot of artistic concessions in the hopes of appeasing Chinese censors.

That's billions of dollars lost. Many films would go from profit to loss.

Maybe we'd see an artistic upside, if they were to stop letting the Chinese box office have so much influence on their art. But it would devastate the industry, and they'd make a lot fewer movies.