The US used to have a streak of "everybody can make it" (back when it had higher social mobility than all of Europe, which isn't the case anymore), whilst the UK's streak all the way from the 19th century was "you should know your place" and it only got broken for a short period roughly covering the 60s and 70s (which, not by chance, was also their peak artistic time, both in Music and the Performing Arts) when anybody did have a chance to make it no matter where they came from.

Outside that, the country was dominated by the upper and middle class who from my own experience living there for over a decade and given my own cultural references when I got there (Dutch and Portuguese) are pretty culturally backwards and prone to being performative in how they act rather than genuine (the contrast with the Dutch is huge), the higher the social class the worst (the culture amongst the "old money" upper class is nasty: for example they will gloat - in a posh way - about any display of weakness, even amongst themselves).

Society in Britain is so stratified into social classes (and, given the pretty much non-existent social mobility, means it's lifelong) that upper class people have their own accent, which is separate from regional accents. I know a number of spoken languages and this is the only country I know where the upper class has its own accent.

As far as I can tell the US doesn't have this deeply calcified social strata with a dominant upper class with unchallenged ideas of what is "prim and propper" dating back to the 19th century, towards whom most of the rest of society looks up and who even have their own schools and ancient univerties providng a well travelled path from Cradle to "Captains of Industy" for their children. I mean, the US does have such people and structures, but they're nowhere as dominant over society and the structures of power (for example, there literally are almost no Judges in Britain which did not attend one of such special schools as children) and what there is in the US hasn't been in place and doing their thing for well over a century.