I have lived through two perfect examples of this idea and have this to report:
Back in the late 1960's I worked for a Milwaukee based manufacturing company (Rex Chainbelt). It came to light that nearly all of our skilled tradesmen were roughly the same age and would all retire in mass in a year or two! We were having a terrible time finding new applicants for an apprenticeship program, the local trade schools were not supplying any with the needed skills (welding, foundry worker, general machining, &c.) with most of their programs being things like dental assistant, beauticians, and such.
The Industrial Relations department came up with the idea of turning an unused warehouse building and some older but still serviceable machine tools into an on site training center. We got dispensation from the Machinist Union to skirt rather close to the edge on their apprenticeship rules. We set the operation up and staffed it with foremen volunteers who would put a portion of each day in as shop instructors. The various engineering departments were asked to supply instructors for basic shop math, blueprint reading, and related subjects.
We started out with a class of about thirty inner city youth. Did I mention that Chainbelt is located right on a major city bus route? By the second week, we had people calling the homes of these kids to ask if we could expect them to show up for school. Did I mention that our students were being paid as machine shop apprentices just to show up for class?
By the end of the first month of the program, we had a full time employee with a company car driving around the neighborhoods and knocking on doors, trying to round up our wayward students. The program did not make it through the second month!
My second experience was some years later at a Racine based manufacturer of hydraulic components. While not nearly as ambitious as the Rex plan, we attempted to provide a basic grounding in shop math, blueprint reading, measurement tools and techniques for some of our younger employees. We found it necessary to include some "grocery store arithmetic" like adding and subtracting fractions and reading a ruler, and other topics that were neglected by our public school system. They went to class for two hours a day, three days a week. The first hour was "on the clock" and they were paid to attend at their base pay rate. The second hour was on their own time. The instructors were all volunteer staff people from the engineering and quality assurance departments.
At the end of the program (six weeks) every last one of our students wanted to know how much of a raise they would receive because of their "new skills" (which barely brought them up to what you would expect from a good high school graduate!). When they were told that they would continue at their base pay until they could move into an apprenticeship program, every single one quit and went across the street and got employment at J.I. Case because they now knew how to read blueprints. Sad but true, and Case didn't even thank us for our efforts.
PS The really scary part of all this is that we're several generations deeper into the pit with the current generation of dead-end kids who are convinced that carrying guns and selling drugs is the only to live.
I would point out that a relative of mine is a liberal arts instructor at a trade high school which provides an excellent and free curriculum in basic engineering and hands-on machinist training in a state of the art facility funded by the city.
The population of the school is approximately 85% Hispanic and African-American.
Out of 800 kids, maybe 50 bother to do the full four years of the program - and of those 50 about 30-35 are white and 10-15 are Hispanic.
One of the retired engineers who is a full-time instructor there told this relative of mine that when he tries to get the African-American teens in the school who show an aptitude for the work to pursue it for a full four years, he gets a response of disdain for the physical labor involved in the program. To quote one kid he was trying to encourage: "What am I? A motherf****** slave, now? Nah."
Any job other than NBA player, actor, record producer or unlicensed pharmaceutical distributor is now "slave labor."
But apparently if these kids are moved from Brooklyn to a rural community like Cooperstown they will wake up the next morning and apply for a job working on a dairy farm and then show up every morning at 4 am like clockwork.