There's an argument to be made - and I'm going to make it - that the reason people keep building new frameworks is that existing ones don't solve their problems

There's an argument to be made - and I'm going to make it - that the reason people keep building new frameworks is that existing ones don't solve their problems all that well. As a result, you can expect them to keep being made, until all their problems are solved. Obviously, there isn't one frontend framework that is perfect right now, and we're not going to get there unless people keep building new ones that solve the problems that come up. Inevitably these will create new problems, that a new framework will solve until there are no more problems to solve!