This was a very good discussion. I was also pleased to see the level of emotion kept to a minimal, since the focus of this forum is analysis, not condolences.
My thoughts are quite different about prevention.
Yes, we agree that we can all kumbaya on the same lesson learned, which is the same "dive only within your training and experience level"; but this lesson with be "relearned" over and over again in the future. I think we should go further.
First of all, since a cave like Vortex is well known and open to the public, why not do more to insure it can be dived safely? Why not install, for example, (1) a minimal system of underwater lights and/or (2) emergency air (breathing gas) stations at key jumps and/or (3) some emergency signaling device and/or (4) highly reliable (not breakable) lines, in a highly public cave.
In other words, since some caves are well known, very public and without any workable means to insure that unqualified divers do not dive there; instead of simply blaming death on the divers, why not make some caves more safer by investing money in one or more of the "off the top of my head" bullet items above or suggest other things/mechanisms/safety devices/controls to make cave diving safer? Not all caves, of course; but there must be some public, well known, caves, perhaps like Vortex, where the owners (or a diving club or association) could invest in making the cave safer for all (trained, qualified, certified, and/or foolish), versus the current "it is an accident waiting to happen" and "dive at your own risk" and "it is always the divers fault because they are not well trained" themes (and "lessons learned") we read about repeatedly.
You should run for congress.