American houses are large and unaffordable. The usual term for a situation like that is inefficiency.
Price per square foot is not a very useful metric, because neither utility nor construction costs scale directly with the size of a house. A 3000 square foot house is not 2x as good as a 1500 square foot house, and it should not cost 2x as much to build. Roughly speaking, walls are expensive, while making the rooms larger is cheap. And bedrooms are cheap, while bathrooms are expensive.
Price per square foot is not a very useful metric, because neither utility nor construction costs scale directly with the size of a house. A 3000 square foot house is not 2x as good as a 1500 square foot house, and it should not cost 2x as much to build. Roughly speaking, walls are expensive, while making the rooms larger is cheap. And bedrooms are cheap, while bathrooms are expensive.