At the time I quit repairing on a regular basis, most sets were relatively new and proved to be really reliable. Most of the time, these newer sets didn't require any real costly repairs. If they did, most owners were reluctant to spend any real money if the set was more than a few years old.
The number of repair shops was on the rapid decline for at least 40 years.
I'll try to come up with more insight a little later.
BTW, I'm another Dave and a fellow cat lover.