Sure, but the fact that React is as fast as those other frameworks, with none of the code overhead of having to manually patch the DOM, is a benefit. React doesn't need to be faster, it just needs to be comparably fast.
What do you mean by "none of the code overhead of having to manually patch the DOM"? None of the other frameworks make you manually patch the DOM, they all do it automatically in their own way.
I actually don't know Angular or Ember well — before React I was largely using Backbone, where DOM patching is manual unless you use templates, so that's really what I was referring to. The benefits apply to those frameworks, too, then, of course.
