In the most abstract sense, I think you have a point, but the reality is that in America, there aren't condos a family of 4 can "comfortably" live in-- it's not

In the most abstract sense, I think you have a point, but the reality is that in America, there aren't condos a family of 4 can "comfortably" live in-- it's not considered acceptable that two kids might share a room, or have a dine-in kitchen. Americans just aren't willing to put up with as little space as Europeans are. There just isn't much overlap in square footage between houses and condos overall-- so I think it's still valid to compare houses to condos. Condos are cheaper because they are smaller. They don't make small houses anymore; that market need is met by condos.