My question becomes: "What defines training and who gets to define it?" Is training just reading as much as possible or is it an absolute must that you find a paid instructor or more experienced mentor to learn?
I tend to be one of those people who pushes the limits slightly but not in such exaggerated ways that will really put my chances of survival at even close to even. I learned rock climbing by leading my very first climb on a 5.8 pitch in the rain. Not typical but probably not life threatening. I just did my first dry suit dives this past weekend without finishing the course. (I did read the manual and have some mentors available though.) I won't ever be doing real caves or bounce dives (with or without training) though, because I have no need to push the envelope that much. I'm somewhere in the middle, mindset wise, of those who want an instructor holding their hand through every step and those who go out and try the most advanced dives after getting their OW card.
Your example of the bounce divers shows my point. The divers said they planned the dive. They apparently considered the need for deco bottles and even used them (???) and completed the dive successfully. Yes, people will always disagree on the safety of such dives but clearly the divers performing them considered the dive and planned accordingly. What extra training is required for something like that? Does the number of previous dives really matter as long as the dive was planned and then dived according to the plan? (Yes I recognize the possibility of emergencies and survival of them changes with dives like this.)
The mentality isn't necessarily about being a pioneer. If that was the case no one would ever repeat any dive, anywhere. Or climb any mountain that has already been climbed. It's about experiencing something you haven't. (Or about experiencing something that others haven't, if it's motivated more by ego than spiritual growth.) Just because you don't have that ego or spirit doesn't mean there's anything wrong with it. Someone has to have that spirit/ego to push us all to the next level.
Also consider that the "odds" aren't really as bad as people think, statistically. More people survive those dives than die. Hence, the odds are actually in the diver's favor, even with the least amount of training.