Driving down costs of building hones substantially is fantastic, if you don’t own a house yet that is. Say the technology gets it done and house prices drop by a large amount, what is a large amount? 20% cheaper? 30? Now imagine all the people who have bought houses in the last ten years before the technology is released. They’d be pissed! And so would the banks.
If someone figured out a way to drastically reduce the price of a house they would undercut the competition as little as possible but enough to be highly noticeable and the savings on material and labour would go into the pocket of one person further widening the gap between rich and poor. This will keep happening anyways it would just be faster. Construction workers out of work due to automation. The price of land would go up too because they want a piece of the savings, don’t forget the small handful of land developers that own half of North America.
I could go on and on on this subject (I’ve been building houses for 25 years) but I’m already starting to ramble.

Houses being made WAY more cost effective is not going to be passed on to the consumer, they’ll act like they’re passing it on but in reality they’re just gonna make home building for the builder WAY more profitable by offering a better price than the conventional builder.