Earlier quoted context omitted.
The standardization in the building trade didn't exist back in the Sears catalog days. For example, 2x4s come in 8ft lengths, using 16 on center studs, 8 2x4s will provide 8 foot of wall, and two sheets of drywall will cover it. And you can order all of the cabinetry, trim, shower enclosures, etc in a form that's ready for installation. A Sears prefab home would not be cheaper today because the inefficiencies that th…
> it's infeasible for a person to construct their own house anymore, given building codes and such What has changed that this is no longer possible any more?
You can do a large chunk of the work yourself (with a crew). But utility hookups are a no-no without a license. And you'll probably need to hire a crane operator at some point. Plus, there are a ton of building codes in regions that are different from other regions. So you'd better get those all right unless you enjoy rework.