I have been in 4 different companies, with a decent to very good salary. React is self-fulfilling prophecy also because developers want to make as much money as possible and companies need more React developers because, at least in my experience, development is so much harder and slower with react - so companies need more react developers, and because there aren't many in the market, price (salary) per developer goes even higher.

So everybody learns React, because companies need more React developers, because development is too slow. Think about it, which developer would prefer framework/library that gets job done quicker and easier, but pays less?