There’s a lot of reasons why this isn’t happening here. First of all, zoning regulations now usually require a minimum square footage and lot size, and these homes would probably not meet the requirements. Second of all, these would probably fall under “manufactured housing “ and even if they have a foundation and are attached as real estate, they’re more difficult to obtain financing on. Third of all, because it’s too practical. This would be great for in fill housing in urban neighborhoods for a start. You could build a community of these in the suburbs, if the suburbs would accept them. Sears used to make homes. They had numerous floor plans, would deliver the kit with all the supplies to the lot, and you would build it. They’re close to 100 years old, or older, and still standing, and are really cool. I have one up the street from me. In the 40’s after the war, you had Lustron Homes, which were built out of ceramic coated metal. They were about 1000 square feet with carports. Really cool and efficient for GIs coming back and starting families. 75+ years later, still standing. You are starting to see houses being built with 3D printers that are really cool, cost efficient, and more durable than stick built homes.