"What I don't accept is the nostalgia of a golden age of stock photography that should be somehow restored to its former glory. I suppose the buggy whip makers mourned the coming of the automobile in much the same way."
Then I take it that you are saying that a Golden Age didn't exist? I know better; I was there enjoying it. As for whip makers - red herring, false analogy, call it what you will.
"Any more than that is way too long in the current stock environment."
With that statement you have just removed the legs from your own stance: in the GA that you deny, stock was used for, and priced, for some very high-value advertising; it was worth spending time and money producing a great original transparency in the camera.
By your own admission, then, today it's a load of crap in, another similar load out, and then straight into the fan and out again all over the world.
Whether anyone can get the system back to sanity I can't say; however, genies and bottles notwithstanding, I do suspect it's possible. It would take a lot of good guys resigning and just letting the cesspool overflow until sanity rules and the plumbers get called back in. Five years? Money talks, and when the sales messages are seen to fail, that money will scream.