We have rich people with average cars as well, what’s that have to do with anything? Some people just don't care about status symbol and drive what suits their needs, and vise versa. This behavior is not associated with NA only, every country is guilty of that, just ask Greece.
If all of the sudden Europe had our gas prices and no extra taxes and costs associated to engine size, I can guarantee you that a lot of people would buy bigger cars. This is the human nature.
I have family in Europe and there is quite a large market for American SUVs and large sedans. They are usually converted to propane just to have a break at the gas pump. People don't go over this kind of hassle because they need a large vehicle, they do it because it comes with a status symbol and they want it.
I can tell you that the rest of the world secretly envies American SUVs and if they could, they would buy them by a boat load. In fact they do, look at some of the Muslim countries and China. Anybody that is somebody over there drives either an SUV or a German Luxury car.
Difference is that over there they don't have the middle class, only elite can drive such cars. In Europe the system is rigged that even middle class cannot afford these cars and again, only the elite can drive such cars. Do you see a pattern here?
US and Canada are pretty much the only countries where a middle class family can afford these vehicles, at least for now...