That's partly because there's no mass, free vocational training for plumbers.

If you tried to scale this up in practice, you'd quickly find that you don't need 3x the number of plumbers that exist now.

Definitely. The trades only make as money as they do because the supply of skilled tradesmen is intentionally limited by selective apprenticeships being the barrier to entry. Today, one can not become an electrician or plumber without said apprenticeship.

Increase the number of electricians or plumbers 10-fold and their wages would plummet.

You assume the pie is static and that more mouths mean less pie for all.

If there were twice the plumbers, the rate per hour would not be halved. There's demand that can't afford these services at the current rate.

I'm sure that's true, but it still doesn't solve your employment issues, and you are just hurting wages for all existing plumbers. There are only about half a million plumbers in the US [1]. Even if you managed to triple the number, you're not making much of a dent in overall employment.

[1] http://www.bls.gov/ooh/construction-and-extraction/plumbers-...

>Even if you managed to triple the number, you're not making much of a dent in overall employment.

But you don't just offer training for a single vocation as that would be silly.

Sure, my point was just that if vocational jobs are naturally X% of the US economy, you're (largely) not 'creating jobs' just by making it easier for people to get trained for those vocations, you're just creating more competition within that sector and driving down wages of existing workers in the process.

That said, it might still be a worthwhile policy to pursue, since vocational education has been neglected for decades in favor of 'college for all', which IMO is misguided.

Vocational training is certainly part of your toolkit to increase jobs prospects for unemployed underemployed people who are willing to work, but it's not the whole toolkit. It helps, but you need more than that.

Those are also highly rigorous jobs that can put a toll on the human body. Not many people really want to retire with pain. That being said, I'm not sure what the alternative for some individuals are. Maybe being on your feet a lot increases your overall well being, I'm not the expert on that.

This is a key conceit - trades don't mean one is less intelligent. A great plumber is easily as intelligent as a great software dev. The left behind are the people who could provide value before, but now can't, and no amount of reeducation will solve that.

Why can't they provide value any longer?

I feel that it is very easy to get trapped in the mindset that I am owed something based on my prior experience. Reluctance to think beyond past experience, fear of leaving behind what I worked hard to learn, or fear of failure in a new area are all things that have held me back in my own life.

I would disagree that people can not provide value beyond what they did before. Except in cases of physical or mental disability, it's more likely a self-imposed barrier.