Many of the service techs went through a TV and Radio Repair program at local tech schools or were trained when they were in the military, but that whole generation is retiring, moving on to other work or are no longer with us. The manufacturers don't want to supply parts for repair, they want to sell finished goods- far less support is needed and they don't need to train techs, supply service manuals in any form (although it's far easier now, with online access or in DVD form) or have dealer tech support at the same level they once did. Now that everything is disposable, landfills and e-cyclers are the only ones who are gaining from this.
When I started working for a stereo store that serviced a lot of equipment, we charged a $9 estimate fee to cover the time needed to diagnose the problem. Some people complained about that and argued about why they should be required to pay it when they had declined the repair. Sometimes, the customer would buy something else and if it was something decent, we'd give them something for their equipment on a trade. We had a pretty extensive used section, so we would repair the better items and sell as used. I would bet that a lot of the equipment that was 20 years old at that time is still working and I'll bet that most of the sub-$200 equipment made now will last much more than ten years.
I keep hearing that we should "go green", but I don't see it happening although I do see that the local land fills are growing. Sure, more trash is recycled, but with far more people buying far more equipment, it's not a sensible way to do things. Economically, it makes perfect sense.
FWIW, I'll be re-capping a 1940 Farnsworth floor standing radio soon, replacing the bias supply caps in my Conrad Johnson power amp, filter caps/bias resistor in my 1958 Fender Bassman and getting an EICO tube tester running so I can go through all of the tubes I have.