I get what you're saying, but "basically the same" is overdoing it. Europeans definitely tend to underestimate the variance from state to state in the USA, but Americans often overestimate it too and you're doing that here. Driving from one side of the USA to the other is a much more culturally homogeneous experience than doing the same across Europe (I've done both). Yes, each state has its own things and I loved discovering them, but they also share an enormous amount. European countries don't have the same level of commonality, and never will without much, much more integration at every level of society (and a bit of amnesia to forget each country's intertwined but very individual history). You can't really disregard language either because it's one of the biggest things maintaining and reinforcing those differences.