So, as I understand it what happened in OTL was that human hunters, due to persistence running and intelligence, were so effective that they could spend just a little time hunting and gathering, and the rest of the day mostly boning (because, what else is there to do?). Then theeir population would rise too quickly, and there wouldn't be enough food, and members of the tribe would die of starvation until a threshold level was reached. And so it went, with cycles of prosperity and starvation, until the Agricultural Revolution.
My question is: Is there a way that some tribal chief or wise man or anybody can get others to stop boning/impregnating, and shrewdly and carefully manage the population levels? A combination of accidental discovery of condoms and pulling out could help this a lot...what do you think, is it possible? In this way, agricultural would never be necessary and humanity wouldn't settle in one place. We'd be roaming the plains right now with our dogs and sheep and domesticated deer in tow, hunting capybaras and gathering fruits and veggies as we walked.