I often hear people on this site referring to the bolded info regarding trades and I'm starting to wonder if that is backed up by actual numbers or just "common knowledge." I have several machinists and welders in my extended family and they seem to have a hard time finding steady employment. It seems very cyclical unlike say accounting or nursing or teaching.
The economy has changed a lot, trades-wise, since the 1980's too. Because skilled trades have been gutted due to the "kollidge fur ev'rywun" trend, the overseas migration of fabrication work overseas, and the planned obsolescence concept that makes people throw things out rather than maintain or repair them, trades aren't what they used to be either. A person who does field work (pipe, welding, rig, heavy mechanic) can make good money but they have to move around and follow the work.
Machinist work is rough. I've got a relative who's a machinist, but he's got no ticket (at age 40, that's a huge problem). There are higher-paying jobs available, IF you have a journeyman's ticket, but in Alberta at least you have to have an employer sponsor you to an apprenticeship program. That of course costs money! So employers choose, instead, to find someone with no credentials and train him to do the basic work. An apprenticeship program isn't available because they don't have a master-certified person to supervise and train. So the trainee, after a few years, won't have the depth of knowledge to go toe to toe with a real journeyman, but they can complete the work the employer needs to have done. I see that happening in HVAC and sheet metal too. The employer's incentive is to hire the least competent person possible. A few apprentice slots may be open, but they go to the "best and the brightest" (that is to say, the boss's son). So there continues to be a shortage of master-qualified tradespeople to supervise, therefore there continues to be a shortage of apprentice starts. This SNAFU won't be corrected until the trade schools start being allowed to admit apprentices who aren't sponsored by an employer and who are self-funding. The risk with that, of course, is that some of the graduates may lack practical skills.
A few people are getting ahead through government or union grants that basically pay the apprentice's wage while he or she does the hands-on portion of the training, but there aren't anywhere near enough of these to go around and the apprentice tends to be put to work doing a bunch of crap work nobody else wants: they're used as free unskilled labor instead of being trained in their craft.
Overall, it seems to me that the trades that are getting it right tend to be in the building domain. Paddedhat may be in a position to weigh in on this as well. The apprentices I've seen so far have been electricians and plumbers, and they are in fact being supervised and their work is being checked. But mechanics is a free-for-all, and anyone can open a mechanic shop with zero formal credentials and still get customers.