I don't think he is suggesting that, rather he is point out that, statistically speaking, such a prohibition would have a large impact on the already low scuba death rates.
In many ways you can make statistics say anything that you like. Something like 70% of motor vehicle accidents are caused by people under 45 years of age. Is it that people this age are just poor divers or do they just represent the vast majority of the drivers out there?
Do people die of heart attacks because they become a certain age, or is it that their fitness and lifestyle (in-particular being sedentary with a lack of exercise) puts them in a higher risk category. Again it's not simply age that's a factor, so I take exception to saying somebody should be excluded from an activity because of age.
As far as diving is concerned, I know many young people that have a certain attitude that's not conducive to safety. I would not suggest however, that this is a result of their age. Because a person is only 25 does not mean he's immature. It should be in all fairness, an individual assessment.
If this was done, I'm sure some people over 40 should stop diving, but perhaps this would be true in all age categories.
I assume you are not just saying more required training (and the associated more training costs). So what standards need to be changed and at what cost/benefit? And how many divers (customers) would those higher standards eliminate?
You have hit the nail on the head. In diver training you have a number of factors at play. Not the least of which is people wanting to make money off the process. You have to establish how much training is required to keep the diver safe? Will this serve the majority of the people interested in this training? How will this affect the diving equipment, research and tourism industries? How will this impact safety? To what level will the Instructors train? etc.
Obviously we all have our personal opinions on this (I've already expressed mine on previous posts). We can look at this from a global perspective, or what it may mean to us as an individual.
There are some instructors who want training to be more through and inclusive (I being one of them) and others who feel "it's just a license to learn," "the death rate isn't that bad," or "raising the standards will affect the industry because of profit loss."
Diving training has changed focus from cold to warm water and from the diver being able to dive unsupervised to supervision required. I think that we need to set-up reasonable parameters and work backwards to enhance safety
and diver retention.