I mean the other 2 countries, Canada and Mexico, how similar are both of them to United States?? Both countries have a similar economy and democracy etc, and I think those two countries share things like supermarkets, stores, etc. I suppose the cultural differences are not a lot, that is very nice.
European cultures had time to develop before travel was easy, so in practice they were much further apart in terms of culture spread. The territorial size argument here doesn’t work.
Of course you’re right, because the US was entirely vacant before a single unified culture simultaneously migrated to all corners of its borders. Weirdly enough, that happened after the advent of trains, cars, planes, the internet, etc. so there was no opportunity for pockets of subculture to develop.
Totally negates my point! I should have thought of that. Embarrassing.