The excessive focus on the nuclear family is itself a very recent trend that would otherwise be viewed as very odd by many if not most historical social organizing systems.

Given the diversity of social models which have emerged globally, I have no idea how you could possibly make that claim.

I have no idea how to argue with you because it feels like we can't agree whether the Earth is obviously round or obviously flat.

From a cursory google search, there does not seem to be anything close to a consensus that the nuclear family is the dominant way that humans have organized historically: https://www.anthropology-news.org/articles/the-persistent-my...

No, I think it's pretty much a biological fact there have been plenty of people without testicles for pretty much all of human history.