This is what happens when you lose forever your very best genetic stock between 1914-1945.
The exodus continued through immigration long after the second world War. Death turned out to not be the only way out of England, and their brightest emigrated to the winds.
Whenever I read books of the political and musical events of the fifties, sixties, and seventies throughout Asia and South America I am struck by how large the English speaking ex-patriot communities were in places like Rio De Janeiro and Hong Kong and Bankok.
That’s not to mention immigration to Canada, Australia, and New Zealand.
It wasn’t Britain’s welfare class that fled.