I didn't pick the lowest cost regions in Italy or Spain either. I am comparing cities vs. cities and not cities vs. middle of nowhere. Both Rome and Barcelona are world class cities. (Barcelona the more modern one). The prices are similar in Berlin and many other cities in Europe expect in Scandinavian countries and London.

There are places where things are even cheaper (especially in Souther Italy), where 3 euros will get you a whole bottle of wine.

While NYC is expensive, is it not much more than either San Francisco or Boston. (maybe a 5% difference, but not 2x).

Just saying