One effect of increasing automation of mass produced parts is that the value of labor goes up because it could otherwise be employed operating mass production.

One effect of increasing automation of mass produced parts is that the value of labor goes up because it could otherwise be employed operating mass production. As a result it can become uneconomical to perform the one-off tasks. Even though the assembly line and the on-site are different categories, they're part of the same economy and partially compete for some of the same labor and jobs. So for example, in the past you might have had a machinist one off you a part. But now that same skilled operator could be programming (or feeding) a couple CNC mills that put out dozens of parts an hour. So the one off machined part is suddenly uneconomical. (Fortunately 3D printing has reduced the specialized skills needed to produce many kinds of parts, temporarily reversing the trend for some things...) Same happens elsewhere, I assume: pipework that might have been welded on site 50 years ago is now often assembled from bolted flanged segments (which are now cheaper due to mass production) or whatever-- even though they're more likely to leak/fail over time. Good news for the people doing the work is that they stay busy regardless. But for those who need the work done, the increased cost of one-off work can be problematic and make some kinds of project impossible to do profitably.