I'd blame the demand on Europe's higher population density and better public transit - there's not nearly as much "need" (demand?) for vehicles that can make long, sustained trips.
It’s only real downside is that luggage space is very limited.
But equally can't overlook the government incentives offered in many European countries and those have been IMHO pretty aggressive, making EV's a very tempting option for consumers.
Though, gas/petrol/diesel is more expensive in Europe and does not have the governmental subsidies many other countries offer and is equally very taxed. Again making EV's, very much cost effective for so many. Some places even offer free charging, if not subsidised charging.
So factoring is the demand for smaller vehicles needing to go shorter distances and those incentives/subsidies, then you can see why EV's in Europe garnering much traction.
I almost forgot congestion charges, EV's avoid those and they can add up in some cities/area's (thinking London for example).
Might be a factor but take a look on the streets of Munich and you'll see a lot of what I call "street-legal tanks"...
They're about status. Plenty of people want something small and cheap, and in London EVs don't pay congestion charge, so the incentive is even higher. But that said, if you're an obnoxious commodities trader who just spent £10m on that new place just off the King's Road, you're probably going to buy your wife an X5 to keep the kids safe...
They just have them as a status symbol because they want to feel important/powerful/rich.
One big difference is car infrastructure, mostly parking: in many European settlements, from most capitals to the smallest village, an unnecessarily big car is a serious inconvenience. Whereas in the US, even on Manhattan a smaller car won't improve the driving (and parking) experience a lot as everything is built to accommodate big cars, just not in unlimited quantity.
This does not keep most Europeans from theoretically desiring a big car, but it makes not spending on one so much more bearable. The narrow streets use-case makes small cars common enough to make them non-exotic, non-stigmatizing also where streets are wide and parking is one size fits all.