Rampant speculation on my part, but I've always suspected that the number of community leaders is small, delicate and disconnected from governments. I've observed that informal leadership in religious communities has an enormous effect on how communities behave - I lived in a town where the baptists organised an almost suspicious number of things for the general community.

I could imagine diversity of religion with no economic incentives to standardise (as would be caused by general poverty) would lead to an element of fracturing in the community. Even without migration, rising trends towards atheism might have the same effect over the long term. It isn't obvious what is symptom and cause in all this though.