I somehow keep ending up working at places where 90% of the employees grew up with staff in the house. Dozens of people with wikipedia pages about their families.

So, people who grew up with staff in the house are obsessed with class. That's perhaps disappointing, but not really surprising.

I'd bet, in the US, you'd find the same among people who grew up with staff in the house. The difference may be that, in the US, it's a lot harder to find people like that.