True, creating value isn't sufficient. But if you're creating value, you don't need that community; that community needs you. That doesn't mean it'll be easy to leave nor that you won't lose a lot by doing so, but it's better than being a leech. Leeches can only survive by finding another victim to suck blood from, and at some point that merry-go-round is going to run out of horsies. Pardon the mixed metaphors.

Philosophically, I agree, but in reality there are so many leeches, who take take take, their whole life, and in the end they are often better off, materialistically than the people, who provided the actual value.