In order to obtain that mortgage, one has to buy into the dominant paradigm.
It was established in the 1940s that a house should not cost more than a car.
https://bfi.org/about-fuller/big-ide...dymaxion-house
As AI kills all the office jobs, there will be acres of commercial floor-space going begging. Archigram addressed this in the 1960s. I can't find the relevant pic.