Atom is very different from other things. The editor component is something that revolves almost entirely about state, and a huge amount of state at that.

I think the future is, like many abstractions, one where your tighter loops escape the abstraction (like numpy's C bindings). There's still advantages on a big-picture scale to using declarative frameworks like React

EDIT: one thing is that a text editor can know a lot better how to edit the DOM after an event (like hitting a character) than React's general algorithm