Egalitarian hunter-gatherers are extremely well established across the global archaeological record, and the pattern for how populations go from that to state-level societies is equally well trodden scholarly soil.

Generally speaking, societies went from having decision-making power shared between individuals and family units; to recognizing one "big man," typically a charismatic leader figure who pops up during crises. His family didn't retain recognition after he died, but once they did, chiefdoms arose. State-level societies arise as the needs of a population become too complex to handle with just crowd logic.

The apes are an even worse analogy. Bonobos, who as far as primatologists are concerned are more closely related to us than Chimpanzees are, live in massive polycules and are well recorded to be non-violent. While we can get some evolutionary info about ourselves based on their modern behavior, we're just working on a different wavelength.

Take an intro to anthropology course.