Unless you've devised a solution to housebuilding that involves homes in desirable locations which take up zero space and incur zero construction costs, this doesn't appear to present the middle class with an alternative to buying or renting the home...

Housing can be very affordable if living in a dense metropolitan area is not a requirement. There are also some efficiency gains happening with design automation and prefabrication that are very slowly creeping into the industry.

I think an immediate option with real benefits would be to provide a small tax advantage for businesses to allow remote/hybrid work. Obviously not everyone can do this, but for those that can, they could live where they can afford to and stop spending hours a day driving to and from an office. Personally, I work at an AEC firm that requires physical presence; however, I have had nearly zero productive in-person interactions in the office. The design team is in another state. Meetings are on MS Teams even when everyone is a few feet aeay from each other. If I talk to anyone, it's purely for the relief of the distraction it provides. I spend no less than 10hr a week commuting.