Wrong, wrong, wrong. Even Jack Woo will tell you not to run his amps for more than 8 hrs at time so they have time to cool off. And when heat is not the enemy, there is still is failure...... I have a Zhaolu dac that never even got warm, but one day just stopped working. I have a barely used Yamaha CD player that also stopped working, and my favorite SS vintage amp abruptly quit producing bass one day. I had a new HD fail in one month. I could go on but you get the idea. Most electronics begin deteriorating from the minute you turn them on and mechanical stuff deteriorates faster. There are exceptions, of course. Cars have improved over the years but still need maintenance. Some of the newer electronic devices and components have a pretty long MTBF, if you get a good one.
Deterioration and burn out can be argued but I'm not married to either concept. The decline can slow, the decline can be fast, and the decline can be abrupt, and some of the stuff, like the Mars Rovers, works well past their expected life times under the harshest conditions.
Um...no. You restated what I said in a different way. I said that most electronics work fine one day and then suddenly break instead of suffering a slow decline in quality before they stop working all together, which is exactly what you described. They don't slowly wear out like a tire, they burn out like a light bulb. They usually suffer a sudden catastrophic failure.
The parts in them may be "deteriorating" slowly, but until this "wear" reaches a certain threshold it does not effect the operation of the device. The majority of the time you never notice anything wrong with a piece of electronics until the whole thing just dies. Its like a regular light bulb. The filament starts deteriorating from the instant you turn it on but do you ever notice anything wrong until its completely burned out? It works perfectly right up until the instant the filament breaks. Most electronics are the same way. They usually operate with no noticeable decrease in performance right up until something major breaks.
That's exactly what you said happened to your DAC, CD player, amp, and hard drive (even though that's more mechanical than electronic). They worked fine until some part drifted out of spec and then they suddenly broke in some fashion. Your DAC didn't slowly get worse and worse sounding until it was unlistenable. It just died. Same with your CD player. The bass didn't slowly disappear from your vintage amp. It stopped abruptly.
Things that slowly get worse over time are usually mechanical. Your tires wear and give you less traction, spark plugs corrode away, seals deteriorate, bearings wear away, etc. These are easily noticeable, cause degradation in function, and usually don't cause the whole system to catastrophically fail. You can easily notice a worn out suspension and still drive your car to the shop to get it fixed. Things with very tight tolerances like optical and hard drives are more likely to suffer catastrophic failure, but thanks to today's amazing manufacturing processes even they manage to soldier on in a half working state quite often. I didn't say electronics don't eventually break and wear out, just that they do it differently from most mechanical systems.