Hmm ... the only reason I'd never use another UI lib again is if I stopped building UIs. It's inevitable that something more interesting to me will come along.
But, the staying power of React has been extraordinary. Individuals and teams continue to pick it over and over and over, which I've never seen before. Personally I used to carry around a "bag of misgivings" about the tech I was using to build UI. React's bag is very, very small.
So, yeah, I'll use something besides React eventually--which may just be an evolution of React or something totally new--but I'm not looking for anything new right now, pretty happy with it even after 4 years.
It's silly, but I still get excited when teaching our fundamentals workshop. React is a lot of fun.