I remember reading about this in "Sapiens". Suppose there were indeed women leaders many thousands of years back. Due to the hunter-gatherer lifestyle, they would not have had any opportunity to both bear a child for a couple of years at least (9 months of pregnancy, breast feeding afterwards) and be a leader at the same time. Add to that the high rate of infant mortality and you have vastly diminishing chances of a leader-woman passing her genes to baby girls. Now compound this over thousands of generations and you will have the society of early-20th century, before infant mortality rates started going down and societies started becoming wealthier that a leader-woman has to invest only a few months at most for a child by outsourcing most of the "gatherer" duties.

I've been thinking a bit along the same lines

Sounds like an interesting book, thanks for mentioning