I'm not sure I agree much at all, but I take issue with your last statement. Why on earth would I ever want to move to anything remotely like ReactJS when I'm building a single user application? You must carry state information, and in that case explicitly having state is both often conceptually simpler, easier to modify/debug, and require far less code than using something literally insane like using js + DOM.
It's good to have varying opinions. I'm unsure what you're considering positive about state. Synchronizing state among multiple widgets in QT for example is a pain and quickly becomes become fragile. To help deal with this, QT 5 introduced a JavaScript based reactive programming framework before ReactJS was popular. See https://en.m.wikipedia.org/wiki/QML#Property_bindings Perhaps not completely an insane idea to some :)
Electron and html5 have a ways to go, but the synergy that can be gained will be well worth the effort, IMHO. Using a browser for quickly sharing research and making basic UI's to interact with computations actually fits rather nicely into the vision Tim Berners-Lee had when created html for browsing information at CERN.
As far as statefullness, GUIs really would be better off moving away from implicit state to ReactJS functional style approaches.