> From 50,000 years ago to 10,000 years ago there were no capitalists, no kings, no slave owners.
Citation needed. Humans have been anatomically modern since 100k BC, including the brain. There is no reason to think there haven't been kings or slaves in that time, just that there is no history about them.
Migratory hunter gatherer bands still exist, and no observation of them through history has found kings or slave owners among them. Nor is there historical evidence. I'm not sure how a migratory hunter gatherer band which has few possessions and moves from place to place would have some slave owners who not work and the others as slaves.
In fact much of the world was like this only a few centuries ago.
Migratory hunter-gatherer tribes have spawned some of the worlds "greatest" conquests - a good example would be the Mongols (who to this day hold the record for largest empire by geography). If it were just Genghis Kahn, that would be the exception that proves the rule, but there a lot more. https://en.wikipedia.org/wiki/Nomadic_empire has a nice list of friendly hunter-gathers and other nomadic tribes that decided to try to conquer their known worlds, genocide their enemies, enslave people, etc...
Citation needed. Humans have been anatomically modern since 100k BC, including the brain. There is no reason to think there haven't been kings or slaves in that time, just that there is no history about them.