Do we have too many JS frameworks?

It seems good people just keep writing more and more of them, I could not help but wonder, is it because people can't find what they look for in an existing framework? I would just fork it add my missing feature and do a pull request... why so many good developers spend all this time on what might be sometimes re-inventing the wheel, just in a nicer package? are there other reasons than pure programming need? or is it just done for fun / education purposes?