Not sure what you mean by much poorer... in any case here is a list of European countries which have a higher median wealth per adult than the US, roughly in order of wealth per adult:

Switzerland, Iceland, Luxmbourg, Belgium, Ireland, France, UK, Spain, Austria, Italy, Malta, Norway.

If you go by mean wealth on the other hand, only Switzerland is higher than the US. But that is not a measure of middle class wealth.

Source: https://en.wikipedia.org/wiki/List_of_countries_by_wealth_pe...