I think React (and Vue) are popular and successful because they meet 80% of the needs 80% of the time, and that's what you want and need from frameworks that are trying to do everything for everybody. They also make it a lot easier to go from a 6-month course into a low level coding job, and corporations are happier because the parts are more replaceable. In my mind, they're rather limited and hard to work with if you want to do anything outside the box, but there are always going to be frameworks because they solve the most common problems quickly.