A big factor is "human nature in nature" and "human nature in high density agrarian societies". Civilization (so far) depends on the principle of a monopolizab

A big factor is "human nature in nature" and "human nature in high density agrarian societies". Civilization (so far) depends on the principle of a monopolizable surplus which allows an elite to mobilize lower ranking elements for games of war and power across geographical distances and temporal distances that would be impossible for HnG societies (bound by the non-monopolizable bounty of the land and the lifestyles possible in such lands)+. An "evil" or "megalomaniac and sociopathic" society in HnG can only extend as far as their adaptive mode of production. Who can gather all the wild fruits of the earth and deny his brother the bounty? An "evil" agarian society can mobilize the monopoly surplus to cajole and punish societal elements far beyond the "natural" borders any HnG tribe would've been able to maintain and into torturous decades and centuries. + - I've read about a few HnG societies where class structures arose because they had some sort of natural monopoly position; crossroads of a regional trading route or salmon run bottlenecks. But the important part is that monopolizable resources "alter" human nature and society.