I'm not trying to tell anyone what the correct solution is (I've experienced societies with wildly different approaches to this), but doing it at the leaf (as y

I'm not trying to tell anyone what the correct solution is (I've experienced societies with wildly different approaches to this), but doing it at the leaf (as you express it) is a solution. It's not the only solution, but it is one. Furthermore, this solution does work to some degree, and it has quite quick results, compared to education which takes generations to impose any real change.