I don't know anything about spiral staircases or masonry I build commercial furniture offices, libraries, courtrooms, etc.

Wondering how finances come out ahead is silly. Take for example take a CNC beamsaw. It does one thing cut straight lines. A person stands in front of it (or a robot but smaller shops it's a person) and puts a board on the machine. The machine grabs and executes a series of cuts. Then you take the parts it spits out rotate them feed them back in the machine to cut the other way. A person standing at a cabinet saw can do the same thing, faster even, with a nicer finish... for the first 10-20 cuts. The machine gives the same 95% quality cut every time in the same amount of time from cut 1 to cut 10,000.

When my shop first got one I by myself cut twice as much material in 1/5th of the time as it took 3 workers on cabinet table saws. And I actually had enough downtime while the machine was running to also put the parts through an edgebander to put a finished veneer edge on the cut parts at the same time.

The 3 CNC machines I run now don't screw up often and waste time or material. Even when there is a problem it's actually often due to user error. I just had to spend some time fixing our 5-axis machine because the operator accidentally left some loose material in it which a sensor on the machine detected to prevent the machine being damaged. The emergency stop it triggered ruined the part and the machine stopped so fast that the machine racked and I needed to re-calibrate it. But that is fairly unusual. Maybe instead of crappy tech they should have bought quality machines? Or maybe the machines were fine and someone should have invested in software instead of a crappy vb script? Or maybe the operators just needed more training?

A master craftsman can use a machine to create the same quality of work in less time if that is the goal. You can steam bend a board and then 5-axis machine it to create a very complicated edge detail that would be tedious to do by hand. Or you can glue blocks up with different grain directions and materials so the completed railing has an interesting design that would be impossible to create otherwise. Or even spend some more effort gluing up those blocks to make a better grain match.

The reason they are gluing up blocks and machining them is because it is cheaper and faster for an okay quality. Almost no one buying the "McMansion" staircase was going to buy your bespoke custom master craftsman spiral staircase. I work in a shop that makes all custom-built to order furniture. Sometimes potential clients call and have sticker shock when they hear the price or sometimes they need to furniture sooner than we can build something custom. They just go and buy something they can live with from a larger company that mass produces a furniture line where they will have inventory.

I don't see an issue with making something affordable for people who want it. I'm not even sure anything is lost, there are still people who will want the high quality product and someone will be there to supply that.

There is whole world between button pusher and master craftsman. Master craftsmen that embrace the technology can expand what is possible. And a button pusher cannot exist unless there is a master craftsmen to do the setup work.