TSandM:jbd, I'm sorry that's been your experience with novices. I guess I've been lucky. I've tried to escort a couple of new divers with really execrable skills -- One I told, after 30 minutes of being unable to get him close enough to neutral to be able to swim underwater AT ALL, that he should go take a refresher course, which he eventually did. But otherwise, we've been able to make progress, and everybody (without exception) has had a good attitude about wanting to improve.
I think mentoring is both necessary and wonderful in the diving world. I don't think many of us could afford to pay an instructor to do the number of dives with us that it takes to reach solid competency in basic skills. (I certainly couldn't!) Generous experienced divers with the patience to do some guiding are a critical component of the process. Of course, it's nicer for the mentor if the student comes with some basic skills (it's hard to dive if the novice can't swim underwater).
Mentors are great but the education system can't assume that every one will be mentored.
While the idea is great, they are certainly not necessary. I had diving peers who were others with experience comparable to my own for the most part. We didn't have the internet then so most of what I consider good diving, I invented. Of course others invented it before me but I didn't know it. LOL
Over the course of my diving, especially my technical and cave training, I have had the chance to dive with some divers who are more experienced than I am but never on a regular enough basis to call any of them a mentor.
The closest that we ever saw to mentorship was some more experience divers that sort of hung out in the same group part of the time. However, even in cave diving, the more experienced divers usually went off to do their "bigger" dives while the newer of us did our own "smaller" dives. If there was anything like mentorship, it was over beers when the diving was done rather than in the water. We tried opening the beer in the water but it all got mixed together and didn't tast very good.
The exception was if you were paying for training of course.
For many if not most divers, mentorship is a myth or maybe wishful thinking. Training needs to be designed and conducted with the assumption that a diver will be diving with some one else of their own skill and experience level.