It's a good - and an interesting point - to discuss. If you ask the folks who look back for 2k years, the most common answer is Christianity, since Paul really ****ed up women when he changed many of the original protocols and traditions in his letters. If you listen to the folks who look back for 5k-10k years, then it's agriculture. I haven't met a single archeologist or a paleontologist who claims that hunter-gatherer tribes were patriarchal, that's just a myth you meet in Internet discussion boards where clueless teenagers think that men hunted mammoths while women collected strawberries. Ie. obviously laughable legends. To me, the most compelling argument is that evolutionary winning strategies where enshrined in tradition and later religion, where they surpassed the reality and thus survived far longer than it was necessary. Definitely the agricultural lifestyle encouraged a more rigid division of labour and societal norms - both of which would be helped by gender-divided spheres of interest/work.