> Prefab homes exist, but they are more expensive than traditional homes per square foot for nice homes that are bigger than a double-wide trailer, so they remain a bit of a novelty (in the US anyway). The fact that the market has yet to find a way to drive down the cost using prefab makes me wonder if onsite assembly isn't in fact the cheapest form of construction at our disposal today.

A narrower set of financing options for prefab homes exists as opposed to traditionally constructed homes. That leads to a pretty serious difference in demand, and an awful lot of the price difference might just come from that.