I typed quite a long reply last night so want repeat, but as said upthread, the big difference was once the role of men in pregnancies was understood the power balance shifted.
Women may have been constantly pregnant or breastfeeding, but as is still the case in many agricultural societies, continued to grow and harvest food.
I think relative strength differences was not the issue, men may have done more hunting because it was easier for them because they weren't pregnant / breast feeding.
The difference is, and we will never be able to say why, that the once is some parts of the world men realised they had a connection to a child, why they then turned into an "ownership" issue. Why didn't it continue that the children remain linked through the mother, why did some societies start to organise into families rather than tribes or clans.
As others have said matrilineal socities still exist.
But is some cultures it didn't for instance mean that a clan or tribe society continued to exist but acknowledged patrilineal relationships, but that paternity was turned into a superior right, and as a result women become properties of men.
This lowering of their status, though many continued to do as much if not more work that before, is what set in train patriarchy ie somehow infering that having sperm made you superior to having a womb.
Did men start or become more aggressive to each other once they became / created themselves as the owners, therefore the protectors of women?
I cant remember which socialist / communist writer it was, but they put forward that the family is the root of women's oppression.
And it isn't a conincidence that improved contraception, ie the pill became more available at the time that second wave feminism became influential.
The problem was / is that during the 70s when women's role in society started to change, men didn't.
So the patriarchal structures, conventions continued and women's liberation became the right to be doubly oppressed, ie go out to work, but come home to work.
Unless and until men change the patriarchy will remain a negative social factor for women.