Especially old people in rich countries often live in way too large houses. It is relativly common to buy a house for a couple with two children. Then the children leave and then one of the couple dies. So you end up with a house designed to house four people having one person living in it. That is why living space per person is going up in developed countries, while especially young people have to pay massive rent for cramped living space.

That is not to say, we do not need to built more and better housing, but that we should look at how we use the buildings we already have and use them better.