Well, apart from the often-documented regular raids from /other/ hunter-gather bands, including torture, rape, murder and slavery. Do you think, absent that $2000 a month mortgage, internal tribal and familial relations would not include abuses of power, including physical and sexual?
Even if you think the current economic and social framework magnified or exacerbated this, can you point to systems in hunter-gather networks that would allow this to be systemically ameliorated at the same scales we now operate, and with the same resource challenges we now face?
(I'd readily agree that there are differences in opinion about the levels of violence and the variation in prehistoric societies, but I think it's worth highlighted the assumptions that your statement makes about those levels.)