Wasn't aware that was the current of thought in the UK, it seemed quite the opposite when I went there once: super cars pretty much everywhere on the streets. Of all kinds and brands...
So I guess there are many twats around there?
As for staying under the radar... Agreed
Compared to almost any other country I've been to, the UK is heaving with top end cars. In comparison in Europe or the US you might spot a fancy car every couple of days if you're lucky.
It's not down to wealth as much as a love of outrageous amounts of credit. I think the UK is the world's most personally indebted economy by a long way.
A supercar in London is just part of the landscape. Elsewhere it's open season from jealous dick heads. Brits do not like or encourage overt displays of success.