All things being equal the price per sqft actually tends to go down with the larger houses, because of simple geometry and the expensive parts (kitchens & bathr

All things being equal the price per sqft actually tends to go down with the larger houses, because of simple geometry and the expensive parts (kitchens & bathrooms) remain fairly constant. AKA a three bedroom two bath 2000sqft house isn't much more expensive to build than a three bedroom two bath 1300 square foot house. Particularly if the designer manages to get most of the plumbing/etc on a common wall. This fact seems to continue through its lifetime if you compare houses in many neighborhoods, the house prices are fairly similar, while the $/sqft will vary wildly.