Something else happened other than the United States’ imperializing of other countries, because it’s been doing that for ages.

Besides repression and propaganda, the U.S. has historically had the easiest road from precarity to a comfortable living (at least for white people), even among imperial powers. So you have a carrot to go with the stick.

First you had the for white settlers, then a generation after the closing of the frontier you had the New Deal, then the postwar economic boom, then the tech boom. People in any capitalist country can dream of striking it truly rich, but for most of U.S. history (again, at least for white folks) it was pretty easy to dream of landing in a spot where you're worried more about retirement and passing wealth along to your kids than you are about putting food on the table this week.

That situation can reasonably be described as a labor aristocracy, but of course a ton of U.S. workers never make it there, or get bounced out.