The actual building materials used to build a house - the lumber, drywall, shingles, etc - are really cheap relative to the cost of upgrading the finishes withi

The actual building materials used to build a house - the lumber, drywall, shingles, etc - are really cheap relative to the cost of upgrading the finishes within the house, as well as the cost of acquiring the land and permits necessary to build (at least in most high demand areas). And of course with the advent of things like power tools and supply chains that can cheaply delivery (relatively) uniform building materials, the actual process of physically constructing the house is easier than ever. So, if you're in the business of building homes, one of the most cost effective ways to make the house seem more luxurious is simply to make it bigger. Also, big houses are not strictly a suburban phenomenon. If you've ever been to a gentrified urban neighborhood it's not that uncommon to see a block where they've torn down almost every 900 sq ft bungalow and replaced it with a 3500 sq ft 3 story box.