3-D printing of small objects was experimental, then expensive, and now is now available at home for small parts. The progression took decades.
3-D printing of houses sounded silly, then was experimental, then was practical for tiny houses, and now is building multi-story buildings.
The price and availability of housing may be about to fall while new types of buildings rise.
“Chinese Company 3D Prints Cement Chateau And 5 Story Apartment Building” – Treehugger
Pretending Not To Panic 