Your comparison makes no sense. React isn't really competing with something like Ember -- the more direct comparison would be React vs HTMLBars (the low level view layer library being used in next generation Ember).
Even if I choose react for my view layer, I'm still going to need infrastructure for managing application state. View layer concerns are probably less than 30% of what I get out of Ember. The rest is bidirectional routing between URLs and models, meaningful controller hierarchies, etc.
React is simple because it ignores all that. But any significant app will still need to deal with those things.
I disagree. You need far less infrastructure for managing application state and if you're willing to settle for the DOM hierarchy communication, you need close to zero, because the communication is endogenous. You can go very very far with only React and a Router without having a mess. There is a default communication layout that is very potent, which makes React simpler than the other frameworks. Even if this were not true, the discussion has nothing to do with MVC...
Even if I choose react for my view layer, I'm still going to need infrastructure for managing application state. View layer concerns are probably less than 30% of what I get out of Ember. The rest is bidirectional routing between URLs and models, meaningful controller hierarchies, etc.
React is simple because it ignores all that. But any significant app will still need to deal with those things.