We have standardized components delivered just in time by ordinary vendors and installed by subcontractors specializing in that work.
It is all commoditized and builders and trades people have choices about who they work with and long standing business relationships.
The inherent complexity of construction is a job shop scheduling problem which is not just in NP it is NP hard.
With a whole additional dimension of human social relationships and woven in. Everyone is trying to solve their own NP hard problem across a different set of projects and under a different set of constraints.
My parents’ home, built in the 1950s was built from pre-fabricated components. From what my dad says (his mother was the original owner of the home), the fit of walls was very poor and they had to do a lot of patching to fill in gaps between the walls and the ceilings. There have been numerous attempts at prefabricated building but all have failed to gain any traction.
A lot of homes in New Zealand were sent over 150 years ago from Australia and Europe as prefabricated kits. Apart from the abysmal lack of insulation, they are still going strong.
Right now most new houses have the wood framing CNC manufactured based on plans, shipped to the building site and assembled, then modified as needed by the builder.
Our roofs are almost exclusively steel, which are also CNC cut and shipped to the site and installed by roofers.
Some Quadrant homes in Washington are built this way. The framing is done in a factory on a gantry and the walls are trucked out and assembled on site. There are subdivisions of thousands of houses built this way.
It is all commoditized and builders and trades people have choices about who they work with and long standing business relationships.
The inherent complexity of construction is a job shop scheduling problem which is not just in NP it is NP hard.
With a whole additional dimension of human social relationships and woven in. Everyone is trying to solve their own NP hard problem across a different set of projects and under a different set of constraints.