I started in COBOL back in the 90s. When I was working in that shop, one of my older co-workers told me about a guy he knew. That guy left his service/repair gig at IBM to start his own shop, he knew how to fix punch-card machines.
For the decade I worked there, my buddy told me that his pal made a very good living repairing those machines, even though they were long out of fashion and 'there was no market'.
Seems the same is true for software, too.