If you are talking about Class A RV's and stuff like that then for mechanic work they should go to the repair shop that specializes for the manufacture of the vehicle. For example, if you have a Cummins engine go to a Cummins repair shop for engine trouble.
For the electrical system on these high end RV's then yes, there should probably be more training.
But,, for my 21 foot TT the systems are so simple that a high school drop out should be able to fix them after a few day course. IF,, !! he is the right high school drop out that is good with his hands and mechanically minded. A lot of kids these days are not. But, I have still met a few of them that are.