That was a transitional period between hundreds of thousands of years of nomadic life as hunter-gatherers, and the adaptation to an optimized form of large, sedentary society. I'm not saying civilizations are ideal. But big societies include standards that call for tradeoffs between what's good for the social order and what's good for most members. One of those tradeoffs is the formation of social hierarchies for the sake of managing the group.

Also, I talk about pyramid schemes in the article.