I'de like to add that many of them seem to hate the idea of doing ANY training whatsoever. This is something I think is happening around all industries (not just manufacturing). For example I was talking to a buddy who works at a place that had someone with 4-5 years experience leave. Now its not a job that needs a particular skill-set/education so you think the choices would be either find someone that has some/similar experience that they help out until they get settled OR get someone green and mold them into a position with a lot of guidance and hand-holding. But no we would rather leave the position open for months until they can find a 1:1 replacement that will work at starting wages like some-kind of worker robot that we can flip on and will do shit at 100% efficiency day one.
Another problem (at least from what I've experience) that alot of boomer management still have the attitude of "If you don't like it then quit/we can replace you easily". It fucking astounds me how people can still act like that when they haven't fixed the original problem of staffing shortage, and are currently dumping all the work on the staff they do have. You think companies would be desperate to keep the employees that are still around and at very least treat them nicer (if not pay them a bit more). But I guess not.
Its all the knock-on effects of individually rational choices leading to a completely irrational system
You want someone who can do the job as cheap as possible, because otherwise you will struggle to compete on cost with your competitors. Your options are to underpay for someone with the skills required (More accurately, underpay for the skills or the workload, paying someone real well to do two peoples worth of work is the same underpay overall), or hire someone who's unskilled who would work cheaper, and train them up to the appropriate level, without adjusting their salary according. However, training is the objectively worse option in every regard - Until the person is trained, you will be missing this critical option, and whenever the person is trained up, they'll demand a raise, or be poached by a competitor. Training is far more likely to leave you paying someone who can't do the job you want them to do, until they take the skills you taught them and leave. Training anything more than ancillary skills to the role functionally never makes sense.
The initial answer to this would be corporate loyalty - But that is actively discouraged. Even if you are loyal in the short term to those who trained you, in the long term the goal is still "Pay someone as little as possible to do the job we want", so you will never see appropriate compensation for the work. This causes stuff like the tech industry phenomena of "Change job every two years otherwise you're missing out on a 50% salary increase compared to your peers". People jump ship to the next most desperate employer who needs the skill yesterday and will actually pay for it, then stagnate salary wise in that role until they jump ship again.
The next most rational answer would be to have an internal career path available instead - Sure, you won't see much raise in the short term, but stick around and we promote internally, and this gives you a long term career outlook and stability, with actual salary increases with the new roles. Problem is, recruiting internally is generally a terrible idea. If you take your actually good people, and promote them into new positions, you end up with an inexperienced person at the new position, and emptied out a role that had someone who was excellent at it. This is a net awful proposition for the organization. The alternative is to promote people who aren't the best at a role but might be better at a higher role, but this leads to organizational resentment, and feeds the peter principle, as you promote the less capable to higher and higher positions. Its almost universally preferable to hire externally for a role, to get someone experienced in a position without also hollowing out another slot in your organization.
But when you glue all this together, you end up with organizations who can't pay people what they're theoretically worth unless they're in a tight situation, can't train people to new skillsets, and can't promote internally to encourage sticking around, so you end up with dysfunctional organizations trading staff faster than the patrons of an LGBT nightclub can trade STD's, with the system being propped up for the staff involved by whatever organization is desperate enough in the totem pole to pay a better rate at the moment - and the cycle become self sustaining as the staff bail from the higher organizations to the better payrates, destabilizing them. The whole things a mess glued together by inertia and apathy.
Then lockdowns came round and blew out the kneecaps of this shambling system of musical chairs, and its all fallen down, and there's no good place to start picking up the pieces.