"anglo cultures" already had quite a lead before WW2, hard to miss that the previous superpower was the British Empire. The outcome of WW2 elevated America, there's no relationship there to broader anglo culture.

Quite a stretch to jump to "everyone might be miserable". Immigration from Latin American and other non-anglo countries is on a scale where it shapes American and British domestic politics, difficult to conclude that those immigrants are searching for the misery of anglo cultures that they can't find at home.