What Exactly Does "Burn In" do for Electronics?

It makes no sense that the expectation is for parts to fall out of spec in order to....

That was never said or implied. All that was is that things don't stay new. Tubes aren't the only things that age due to heating up. Anything electricity encounters the slows down it's travel heats it up. So cold, out of the box won't and can't sound the same as when on for awhile.

A really stupid attempt...

Really? Is this baggage from some older thread?

Nothing I know of sounds best, functions best, drives best, or operates best until broken in. Please name one thing that does.Then there is a long period of great performance. To say that it only doesn't apply to electronics is goofy, to be polite.

The signal doesn't magically travel through cables, capacitors, tubes, traces and the like and not leave a trace or have an affect. That affect is the lessening of the time it takes to sound it's best.

All the best,
Nonoise

I get that certain technical specs are sometimes required and that there is a descending scale of quality. I was referring to the unmeasurables. You know, those invisible attributes that always exponentially increase cost more than materials and labor.

Nonoise, you didn't take that personally, did you? I was of course generalizing. No offense.

Infer, imply, suggest. Call it what you will but I know what I read. Perhaps you misread the previous post?

Csontos, I didn't know what to take and am sorry if I inferred incorrectly.
No harm, no foul.

All the best,
Nonoise