This is fair / you're right: I was mainly thinking of banking, consulting, law, and buy-side finance. As you say, though, there are plenty of highly-trained professionals who don't experience a 5x earnings increase over 10 years; functional medical roles (e.g., anesthesiologists) come to mind.
Something I was wondering when I wrote the original question -- and I may be way off here -- is whether there are cultural or structural effects in tech-industry programming that cause wage stagnation. For example, there is less wage stagnation for programmers in quant hedge funds than there is in the tech industry; part of this is the clear p&l, of course, but perhaps there is a cultural / structural component as well? I'm not a programmer, but I once heard something that stood out to me: A friend, who was a senior programmer, discovered an inefficient process where he worked. In brief, whenever a certain "event" occurred, the company lost money; the senior programmer noticed this, and built a fix -- no more "events", and hence lots of money saved. From what he told me, my back of the envelope was that by building this (which took him about a week), he saved the company more than $600k a year. I mentioned to him that if he had come in as an outside consultant with a black box solution and offered to charge $100k a year to save the company $600k per year, there was a nonzero chance they would have said "yes"; he laughed and shrugged. This made me wonder whether there is something intrinsically non-value-capturing going on; perhaps (1) tech-industry programming doesn't have a culture of individual-value-capturing, or (2) the role of a programmer doesn't have the structural leverage to reliably capture value. Of course, this story is just anec-data; there may be no conclusions here.