2) Tribal gatherings grow unwieldy enough that they require management and support year-round 3) year-round management and support requires agriculture and taxes 4) year-round managers grow pointy hair, lord themselves over the hunter-gatherers 5) Hunter-gatherers decide they're sick of the pointy-haired managers, call off civilization, convene next year's party somewhere else Burning Man.1) tribes gather at regular intervals to party, trade, fuck, dance, settle feuds and otherwise maintain the stability of individual tribes within a larger network of tribal culture
Literally. Or Saturnalia. Or Mayday. The tradition of "the lord of misrule" has archeological evidence going back seven thousand years or something. Paul Kriwaczek wrote a great book about the Babylonians/Sumerians /Akkadians and opens it by pointing out that pre-biblical culture lasted, uninterrupted, longer than civilization has lasted since its fall. He also points out at length that if we were to draw any comparisons to modern cultures, the parallel would be the Soviets.