Actually class D has nothing to do with digital, and even though YOU may have had more reliability issues with class D amps doesn't mean that's the experience that others have.
Class D is actually more forgiving of power issues, and the protection circuits are far more effective in protecting the amp from failure than the older gear. Many of the newer class D amps with SMPS will work perfectly well all the way down to 100V, which is better than most conventional power supply amps. The better protection circuits shut the amp down BEFORE damage, which is why the better class D amps often offer longer warranties than the conventional amps.
NewI am only concerned with what I have experienced. I did a gig recently that required the use of a generator; my GK MB500 went into protect mode, my Ashdown 1/15 combo did not and worked like a charm (I love my GK micro heads and will never get rid of them). I did a gig at a coffeehouse that had a history of questionable power with a Carvin 500 watt class D head; it went into protect mode and I had to use an old back up Peavey head that didn't even belong to me. I briefly owned a TC Electronics 200 watt micro head and it did the same thing that the other ones did. Different speaker cabinets were used in all of the examples and the speaker cables were of high quality.
That sure seems to be where it's headed, I get the auction notices for the pro audio and production industry and it's really pretty grim.
It depends on how qualified you are as a tech. A properly qualified tech should have no problems properly servicing PCB based products, I know that I have for almost 40 years without any difficulties. As a company, Mesa still services it's early PCB based units that go back close to 50 years now, not a problem at all. is your amp worth servicing depends on how much you value it, and if your tech is capable of servicing it cost effectively. Great techs are not necessarily expensive if they are efficient at their craft. Less qualified techs i would have to agree with you on, it is becoming a challenge, but a poor tech is a poor tech no matter what amp they are working on IME.