Tell this to the widows and orphans of those that have died in caves.
Also I would wager that 90% plus of those cave fatalities would not have been fatalities in open water. (allowing 10% for medical issues even though cave divers are likely in better physical condition on average than many OW divers)
As in any endeavor you will find there are old cave divers, bold cave divers, but very few old and bold cave divers, aside form the terminally ill trying to call in on a policy.
Being competent while developing knowledge, experience and a mindset has nothing much to do being old and bold divers argument. It was decades ago “I think” people were debating what is best way to do things people were claiming some were doing it wrong some were doing it right.
Today we are pretty lucky in terms of equipment, knowledge and training opportunities. No need to “discover” or “DIY” things.
Incidents, accidents often don’t happen themselves, multiple bad decisions takes things there. I can’t comment about widows and orphans apart of my sympathy for them, but SCUBA diving is dangerous activity and an extreme sport, which may lead serious injury or death. I made my piece with that idea. Like many things is in life, every decision is a trade off, badminton could be safer alternative.
Another thing is, when i say cave diver is safer in a cave than open water diver in a sea, it is not “only” about taking four day course. Understanding, knowledge, mindset, equipment, knowing limits all goes together. Not all divers and all dives are same.