Those smaller tribes were continuously at war over resources... It's exactly the behavior we observe in nature whenever resource scarcity presents.

A world without private property leads to a world of pure lawlessness. Sure... We could do that, but it would quickly devolve into forever warfare where only might wins, and even that for only fleetingly small timeslices.

History's progression has proven that exploited workers still prefer to exist in that system vs one of continual peril.