You're right. It is a complex problem more akin to Christian missionaries who tried to bring their religion to the country that they visited. The country/culture might actively resist change because it threatens the status quo. Can't just build churches, have to build a following. And, as the Crusades showed, that can lead to aggression and war.
For the US, replication and forking off improved variants of the Harlem Children's Zone somewhere other than Harlem
http://en.wikipedia.org/wiki/Harlem_Childrens_Zone