I used to do labor market and skills forecasts for colleges and the private sector.
I sort of fell into it after volunteering to do career exploration classes for laid off/displaced workers. They were being fed so much misinformation about careers, particularly from community colleges pitching "the next big thing" career path - IT, web design, green jobs, etc. The more I looked into it, the more that it didn't make any sense.
The pitches were exactly as you describe. In the early days of an occupation, it pays well, then becomes a commodity, then gets outsourced. It didn't make sense to pay for training for the hot new thing. Those jobs would be filled by neighboring occupations by the time they had finished training Then they would be competing with a larger pool of experienced folks, and carrying student loan debt.
I got hired by the colleges that were trying to sell the new occupations and programs to research future demand. Didn't last long because they did not like what I was saying. They got a lot of grant funding to develop and sell "new occupation" training. The exception was old occupations - chemical plant technicians. I worked a lot on their curriculum revisions.
I revamped my career education courses to teach people how to evaluate the life cycle of occupations and training and to avoid taking on debt if the ROI wasn't there. Basically career caveat emptor. I never made money doing it, but hopefully kept some folks from making terrible decisions.
I also retired poor, but feeling like I might have made a difference to a few.