It is true that Italy is not affordable at all for young, unmarried people, despite being overall more affordable than Europe average. It only makes it clear how bad the situation is in Europe, and how Americans have no idea how good and affordable housing in US is.

At the same time, prolonged living with parents, and multi generational households have, for many past centuries, been rather common in southern Europe, much more so than in the western, or, especially, northern Europe. Very high rates of living with parents is not necessarily indicative of economic situation, one also needs to consider cultural patterns.