Plutocracy and reproduction.

The concept of one male and one female committed pair bonds as a social norm is a reasonably recent invention, conceived apparently on grounds of fairness and societal stability.

For a long period in human history, a plutocratic male elite reserved multiple female consorts for themselves, and a great proportion of males never successfully reproduced their genes.

Whether due to class issues, slavery, or war, it seems clear that most males in such societies were considered as expendable by the incumbent tyrants.

We are, collectively, the descendants of an exalted few.