I think you're missing another important factor. TV repair was a major source of employment because early TVs were highly failure-prone! A TV was usually the most complicated piece of electronic equipment in the house. It would often have dozens of tubes that could burn out, and older models were assembled with point-to-point wiring (instead of circuit boards) which was prone to short circuits. It wouldn't be unusual for one to need repair or tuneup work a few times a year.

Modern TVs, by comparison, rarely require repairs. A new flatscreen TV is likely to provide continuous, problem-free service until it is obsolete. That's the real reason why TV repairmen are rare now, not because TVs are cheaper or harder to repair.

Human rights violations in countries like China is to blame for reducing the value of skilled labor.

That said, it's been interesting to witness the recent rise in YouTube repair guides coupled with online parts stores. Obviously not for everyone, but I've had good results repairing two different washing machines, a stove, a coffee grinder, my hot tub, a laptop, a video game controller, etc. For a lot of those I would have felt completely overwhelmed and not known where to start without a video tutorial.