It already is, and in great quantity, done with prefabricated panels. I worked for one of Quadrant Homes' builders in the PNW about 12 years ago and our framing

It already is, and in great quantity, done with prefabricated panels. I worked for one of Quadrant Homes' builders in the PNW about 12 years ago and our framing came out pre-assembled on trucks. We would then nail it all together. They even boomed up the bottom and middle floors pre-assembled and nailed them together on-site.