Who says you aren't going to do progressive penetration in a cave. You absolutely should learn the cave before continually poenetrating further
Really? Cave diving with no line? I don't cave dive, but if you say that you do that, I'll believe you.
What spearfisherman do don't have any bearing here or to the discussion on quality of instruction. There's crappy looking cave divers who pus 1000s of feet. That doesn't mean they can teach safely.
I guess the question comes back again to what you consider a good diver (as opposed to a safe diver). And I think that the skating analogy is appropriate.
A figure skater has not the slightest bit of excessive motion. Every move is precise, poised and perfectly balanced. Points are deducted for minuscule wobbles or a slightly misplaced foot. The whole point of the sport is excruciatingly fine control over body position. Hockey simply is not the same thing, you don't need to love poutine to understand that. Yet those athletes are also supremely skilled at their sport, and compete at the highest levels. So are figure skaters "better" skaters than hockey players? Are hockey players "crappy looking"?
Seriously, not everyone has the same goals. Doesn't necessarily make them unsafe divers.