Nothing compared to when you get a house as a couple. Rational pricing and cost-benefit analyses go out the door when the emotional buttons hit on some overpriced place.
A big house can have value, but not the way they are typically built in the US. A valuable one has a big-enough living section with a separate workshop, gallery, or apartments. American zoning laws tend to forbid it, so the workshop is often labeled a "garage". Your garage can be as big as you like, but you may be obliged to conceal how you use it.
Strange but true, Americans have been taught it's normal. Like diamonds.