What I don't understand is why these trades are not taught in prisons. Maybe they are.

But if you want to cut recidivism and train people to earn a living wage honestly, why not push plumbing, auto repair, and electrical?

There seems to be an outsized emphasis on food service in prisons, maybe because it is convenient for the institution and saves them money?

I would assume that since they're in prison, they'd have trouble passing the requisite background checks for licensing or employment...Especially for in-home service jobs.