Hmm!
I think the idea is to have a workforce that can migrate between jobs as work becomes available in other areas.
In other words, if there is no Plumbing about you should be able to retrain as a Joiner, Sparks or Welder if there is work in those areas. In other words be multi skilled.
To me they should widen it out to include Doctor, Solicitor, Accountant and so on and that is only for starters. The Professions are heavily protected though and you can't get away with it or get in there. The Plumber and construction trades are free game to all.
You could have other trades open of course such as miller, welder and so on. But there is virtually no manufacturing industry jobs left, so they all pile into construction.
I am not a fan of Maggie Thatcher, but she was trying to break up the professions as much as they could be broken up, to allow others into them, but no luck so far.
Mind you I don't fancy going to a fast track three week course doctor. But lets be honest much of the work a doctor does could probably be done by others. The nurse practitioner is an example.
The law is another area, but how do you get into that, the lawyers write the laws possibly to keep you out.
But they could do something. Its governments job to regulate. You can't leave industries alone to govern themselves, the financial crisis shows that