So, the question is: 'Does a thing a smart guy told us about computer systems in 1967 holds true now, 59 years later, and does it apply to my particular technology'? :)
React is not representative of how Facebook's whole tech stack works. It is a small composable piece of tech they created, then open sourced, then it was shaped by many external forces, and then was adopted by thousands other big and small companies and individuals.
Also, you are not Facebook, but you are also not Basecamp/37signals.
I have written a lot of VanillaJS and a lot of self made framework-like code, plus I've used the one off creations of other developers. React is far superior.