>> This is one of the main issues of open source - people tend to work on what seems fun/interesting/rewarding. As a result a lot of people work on different implementations of the same things instead of coming up with one good solution and creating new things on top of it.

You could say the same thing about commercial software (and other) development. They just call it competition. In business they claim it is efficient and drives innovation. In open source it's said to be inefficient and a waste of time.