From 1908 to 1942, you could buy houses through Sears catalogs. Sears sold about 70,000 of them throughout the US and Canada, and you could pick from 370 different styles. The cheapest models were about $360 (in early 1900’s dollars).
Although Sears houses haven’t been sold for well over 80 years, some people in modern times still build homes based on the old Sears plans, since they used fairly standard materials and many models were designed to be easily constructed by the homeowner.
Here is an ad for a large, 10 room model which sold for $6500, and an actual example of one,
It’s mostly because of zoning laws. Large minimum lot sizes force the land to be expensive, which means that in order to improve it enough to make a decent profit the developer has to go multifamily (if allowed) or very large single-family. A small single-family house is only possible in the exurbs where land is still cheap.