Rob, having lived on both continents, I think your perception is quite correct, as much as broad generalizations could be. I would say it is not specifically British (sorry!), but European. I tend to think it has something to do with Christianity, particularly in its Catholic incarnation (and pardon me if wrong, I do not claim to be a religious scholar), in particular the saying "it is easier for a camel to go through the eye of a needle than for a rich man to enter the kingdom of God".
I'm starting to suspect that, too. I've come across several people here who seem
quite well off, but still spout rather leftish views; in particular I'm thinking of a couple of them who own businesses here. It appears to me to be a bit of hypocricy or, perhaps, a public display of playing safe? Something I noted thirty hears ago on first coming here to live, was that the local rich didn't spend their money on swanky cars; one multi-millionaire that I know uses the same small, workmen's bars as the rest of us, drives a modest mid-range family car and at best, as far as I remember, owned a rather small ski boat. And in those bars, chats to absolutely anyone who cares to chat with him. In a way, it's reassuring, but it also disappoints a little: I'd like my millionaires to play the part! The world needs more glamour. It reminds me of the sad claims of British football pools winners of yesteryear who used to say that a win wouldn't change their lives, that they'd continue working in the factory... as if their erstwhile mates would allow them ever to feel the same again!
But the expensive car thing seems to be growing here too, now, these past few years, mainly spurred on by the next generation that has a liking for spending the previous one's wealth. And also by the buy-now-pay-later ease.
Oh well, maybe Saturday morning's computer check will see the Euromilliones come my way. Have to say, I feel a certain sympathy with the 'not change my life' school: what would I do differently now? I doubt a boat would come to fruition and at best, a 3-Series BMW coupι or a medium-sized Mercedes; I don't really desire large cars - far too restricting in the where-to-park stakes. Perhaps I'd just call cabs? However, I'd certainly make my kids independent for ever! Or until the next financial crisis.