In The WEIRDest People in the World (2020), Joseph Henrich argues that over a millennium, the Catholic Church simplified the kinship system of the West from clannishness to the nuclear family. People stopped marrying in a narrow circle, which results in narrow genetic loyalty—clannishness—and started marrying in a wide circle, which results in wide genetic loyalty. Cooperation scaled, and the West, with its big-scale civilization, took over.

Henrich doesn’t argue this, but my understanding is:

1. There have always been clannish holdouts (e.g., royalty, the aristocracy, the Jews, the mafia).
2. The clannish holdouts end up with a lot of power.

What was monarchy but that? That is, what was monarchy but the clannish holdouts controlling the non-clannish? The non-nuclear families controlling the nuclear families?

And what was the aftermath of the World Wars but the end of royalty and the aristocracy?