> Europe for an hour and ask them after which differ more, I would bet serious money they will always pick the two European countries.
Only because of superficial things like language. When it comes to politics and the role of government, Europe is pretty consistent. Barring language and architecture, this makes cities all effectively the same pattern (high density, trains, buses, expensive per sq foot).
The gulf between life in the sprawl of Dallas and the density of NYC is far greater than the difference between Paris and Rome.
OP also conflated regions and countries. I read it as they were comparing US, EU, and India as a whole. Also curious where their perspective came from.
My point is that the presence or absence of cultural variation in one place does not equate to a lack thereof in another. Just because someone hasn't seen it, doesn't mean it doesn't exist. Culture isn't based on comparison, it's something in its own right
The variations across Europe (I can't speak for India) are on a completely different level. If you put a random person into two different states in the US and two different countries in Europe for an hour and ask them after which differ more, I would bet serious money they will always pick the two European countries.