I think it's a bit of both. React introduced component based programming, wich was great. This was copied by many frameworks. But React held the first position because of it's strong base, and because it was just very nice and good in general for a long time in the first years of React, 12 years ago.

But React has kept hold to the virtual DOM and JSX for over those 12 years. While other frameworks have created more innovative rendering mechanisms, resulting in faster rendering times with simpler code.

So for the seasoned FE developer, they know there is better out there, but 9/10 jobs ask for React. And people don't seem to be interested in trying out some technology that is actually easier to use and results in a better end product. Because they are not familiar with the name, and they don't know anybody that made money with that, so better safe than sorry.

So, React has been great, but by now it's a bit of a pain in the ass sometimes.