>Sure, they have a passport - or multiple - but they'll emigrate to another country without blinking,

You forgot one variable. Women have a mind of their own.

Switzerland tried to take London's Hedge Fund Industry. The wives and kids hated the lack of things to do compared to London.

Same with Footballers. If a football player or manager signs for a club in a unattractive location, the wives may stay in the previous City.