tech employees do far less work now than they did 10-20 years ago

Agreed!

Of course, if we had truly understood the situation 10-20 years ago, we could have admitted that they were primarily being paid to know how to get the thing* to work, and not actually for the hours they spent typing in new code. Hence the rise of "Infrastructure Engineer" and "DevOps Specialist" as titles.

*I omiitted the technical term, for brevity. But to be clear, by 'thing', I mean what professionas typically call the "damned fucking piece of shit webserver, and this fucking bullshit framework".