Why do these structures seem to come about so very easily in the first place? What is their pattern of evolution? What functions do they serve (ideal and actual) -- and are those functions changing?
One specifically modern context thought: has the religious social structure become the primary source of stability/familiarity in most individual lives? (Building upon an earlier hypothesis that as human beings, we are most comfortable with the familiar.)
If system we need: could (should) we create a better one?