I see, every time I go and down the NJ Turnpike, the ad for the local heavy equipment union - right in front of their "training area", with cranes, dozers, etc. So it's not necessarily not happening from my perspective.
I just went through some contractor invoices for one of my government clients - they have to pay the guys prevailing wage - the apprentice was making $14/hour. Anyone with a level of skill and experience was not less than $30/hour. Top level guys were making $65/hour.
I don't know if they work 2000 hours per year at those salaries, but these are some good numbers, for that level of education.
Get into some of the trade unions in NYC, and they sky could very well be the limit.