> most prefer to experience 2 childbirths. A few will go for 3, in case they didn’t get a boy or girl, but the amount that want more than 3 is basically negligible.

I guess in societies that hadn't succumbed to nihilism, what people "prefer" was less of a direct line to what people would do.

> health or physical risks women face in partnering up with a man, pregnancy, childbirth, breastfeeding, infant rearing (lack of sleep),

> harassment and violence against women

> doesn’t make sense for women to partner up with the bottom 10% of men? Or even 20% of men?

It seems clear where you are coming from is about female victimhood, and yes, I agree that biologically there are inherently risks. I'd argue that Western society mitigates those with orders of magnitude less maternal childbirth mortality, and balances them with legally enforced child support and alimony. The risk to the father is that he has children with someone who will change and treat him like dirt, leaving him to choose between staying there for his child and being miserable, vs leaving and being financially ruined and potentially unable to move on.

But it's wild to me to suggest that one in five humans who are male deserve to be Forever Alone. Obviously the "bottom 20%" of women by whatever measure you think determines "worth" should be with their "bottom 20%" male counterparts.

I agree though that what you describe is what's being practiced. Studies have shown very clearly that if you get everyone rated by attractiveness (such as by polling a large group to rate each person) and ask each woman which man she would accept, even the 1s and 2s will not consider the male 1s and 2s, and in fact most will not even consider the 4s and 5s. The male 10s and 9s are all drowning in options, the 6-8s are eventually finding someone, and the 1-5s of both sexes are having a hard time forming relationships. The women are alone because they think they deserve 9s and 10s, who have "better" options and thus will only temporarily use them; and the men are alone because essentially zero women want their attention.

The outcome of the above mismatch does seem to totally make sense with collapsing fertility.