This is also true for a lot of the "kits": they're not particularly inexpensive for the floorspace (especially considering the labor needed), and often require a lot of finish work to be livable. If you have the land, manufactured / modular can end up being more cost effective and considerably quicker.
These strike me as schemes to mark up materials moreso than honest efforts to provide affordable housing.
I never understood it either. The 3D printed houses look like unfinished throwaway housing. The type you would build as a homeless shelter or refugee camp. When it is time to tear it down, you somehow reuse the concrete in the next house. That is the kind of impression or "vibe" these houses give me.
