When my father joined an attorney's office as recently as the 80s, there was a whole team of people that worked with: Of course, there were the attorneys who actually argued the cases, but also legal assistants who helped create various briefs, secretaries who took dictation (with a typewriter, of course) to write those documents, receptionists who managed the attorney's schedules and handled memos and mail, filing clerks who helped keep and retrieve the many documents the office generated and demanded in a giant filing room (my favorite part of visiting as a kid: row after row of rolling shelves, with crank handles to put the walkways where they were needed to access a particular file), librarians who managed a huge card catalog and collection of legal books and acquired those that were not in the collection as needed... it was not a small team.
When he retired a few years ago, most of that was gone. The attorneys and paralegals were still required, there was a single receptionist for the whole office (who also did accounting) instead of about one for each attorney, and they'd added an IT person... but between Outlook and Microsoft Word and LexisNexis and the fileserver, all of those jobs working with paper were basically gone. They managed their own schedules (in digital Outlook calendars, of course), answered their own (cellular) phones, searched for documents with the computers, digitally typeset their own documents, and so on.
I'm an engineer working in industrial automation, and see the same thing: the expensive part of the cell isn't the $250k CNC or the $50k 6-axis robots or the $1M custom integration, those can be amortized and depreciated over a couple years, it's the ongoing costs of salaries and benefits for the dozen humans who are working in that zone. If you can build a bowl screw feeder and torque driver so that instead of operating an impact driver to put each individual screw in each individual part, you simply dump a box of screws in the hopper once an hour, and do that for most of the tasks... you can turn a 12-person work area into a machine that a single person can start, tune, load, unload, and clean.
The same sort of thing is going to happen - in our lifetimes - to all kinds of jobs.