Right next to my $1.85M San Jose single family house (1300 sq ft, built in 1959, very unremarkable), there's a plaza with a Dollar Tree that is almost always empty.
In comparison, a "Mobile Home" in the same area would only be $400k [1] , with similar house size and build quality. It's a lot cheaper because you don't own the land.
There are cheap housing options that already exist but they typically have a stigma. This 3d printed home is quoted as 3x more expensive by area than this existing option: https://www.claytonhomes.com/homes/21TRU28563RH/
Consequentially, manufactured homes often have to be built in unincorporated areas which don't have zoning restrictions.
Now all we need is some robots to clear-cut all the useless vegetation that's occupying the land that these future wonder-developments will sit on.
That's culminated in excessive demand for housing in areas that are already heavily developed with existing structures and land-use, and pressure for demolition/reconstruction and rezoning for higher density, which is not easy to achieve.
Modular, manufactured, and kit homes are almost universally single family structures which don't do much for that problem. They have a place in ADU (accessory dwelling units) construction that marginally increases density in some neighborhoods or certain kinds of creative urban developments, but mostly just make it easier and cheaper to build out new land in those places that many currently don't see as desirable.
That said, in the big picture, continued innovation in that sector helps ready for the inevitable pendulum reversal as people recognize their urban centers as inaccessible and/or blighted and adopt a new vision of their own future. But that's not a "today" solution or really something that can be controlled very well at all.
These strike me as schemes to mark up materials moreso than honest efforts to provide affordable housing.