That stuff really isn't that expensive though, I mean it adds up, but the real cost is the multi levels of labor mark ups going through contractors for the labor to ultimately be done by someone with very little experience making very low wages.

You will have a "builder" who hires a GC, the GC will then hire subs. The subs will bring in crews and the crews are typically two guys with a truck and whoever they picked up at home Depot that morning.

Every one prices per job except the home Depot laborers that end up doing all the work and they get like $100 / $150 a day cash. But they are who is doing 90% of the work.

In the 40s when you hired someone to build a house they actually built the house, like would be out there sawing or even straight up milling the wood themselves.

Today almost no one that's experienced does new construction where they actually do work themselves. The actual quality workers are all in remodeling because the price to time/work/labor ratio is so much more profitable.