It can be more than one thing. But one of the interesting possibilities for housing is modular construction. You mass produce homes on an assembly line as walls prefitted with plumbing and electrical, put them on a truck and snap them together at the site. Now you can produce them wherever labor costs are low and assemble them in a matter of days or weeks rather than months or years.

This doesn't get you out of zoning restrictions but could allow you to recover from their historical effects more quickly after zoning reform is achieved.

People keep saying this, and it keeps not happening in a significant way as described. Trucking assembled parts is harder than trucking the parts, which tends to limit the distances assemblies are trucked. It becomes cost efficient to truck construction workers (even if it's not great for the workers).

That said, some assemblies have become pretty common, I think preassembled roofing trusses are frequently used in favor of framing on site.

> It becomes cost efficient to truck construction workers (even if it's not great for the workers).

This gives me a different idea and I wonder if it's worthwhile.

There are industrial robots that e.g. mass produce cars. Suppose you make one to mass produce housing, but instead of putting it in the factory you put it on the truck. Put it on the construction site. It takes a pile of lumber, cuts it to length and turns it into walls, puts the pipes and wires through the walls etc. This is the kind of thing that existing industrial robots can actually do if you program them appropriately.

Then you send it across the street to put together another building. Assembly line, but the products are big so instead of moving the products to the next station you move the robots.

I’ve worked on those robots that mass produce cars. The idea that you can ship them from site to site doesn’t really work. They require a lot of support infrastructure. The use a lot of large parts (dies in the case of cars) that are heavy and must be constantly swapped out. They require a lot of constant tuning that would likely be made worse when subjected to the vibrations of transit. They require whole specialized teams just to maintain.

Those sound like things that are actually specific to cars, which operate on metal with tight tolerances because it e.g. has to hold compression in a cylinder.

Houses are made out of wood and tolerances are measured in centimeters if not inches.

This sounds like conjecture from someone who hasn’t worked in construction or automation. I’ve worked in both. Problems generally seem much simpler when we don’t have much experience with the nuances and details of execution.