One important factor to increasing house size is that localities in the US tend to have fairly large lot sizes. To recoup the cost of building on more expensive land, builders build more house, because the opposite (building 2 or more houses and subdividing the land) is just illegal.
One important factor to increasing house size is that localities in the US tend to have fairly large lot sizes. To recoup the cost of building on more expensive land, builders build more house, because the opposite (building 2 or more houses and subdividing the land) is just illegal.