I define scuba diving RISK as: "The number of mistakes you have to make before it kills you"
The 'riskier' the pursuit, the less mistakes you need to make before it all goes dark.
Tech diving can kill you immediately if you make one stupid mistake (i.e. gas switching). That is a high risk activity.
Open Water (Buddy) diving allows you to make a lot of mistakes before it kills you. It is a Low Risk activity. For instance, the following is a 'chain' of mistakes:
Mistake #1: You run out of air. Solution - share air with buddy, ascend. Live.
Mistake #2: You are separated from buddy. Solution - conduct CESA to surface.
Mistake #3: You are too deep to CESA. No solution - drown. Hope someone resucitates you.
Solo diving reduces the error chain before fatality. It increases risk.
More risk + more mistakes = more deaths.
Additional diver training and experience reduces likelihood of mistakes. It is the natural way to balance the risk-mistake equation.
So... why do some people seem incredulous that it is recommended that divers gain more experience before embarking into more high-risk activities?
There's so much you don't take into account. All of this stuff you talk about, you talk about in absolute terms, but it's not nearly as absolute as you seem to think it is.
What if a person is worse off with a buddy because that buddy is incompetent and thus puts the competent diver into situations he otherwise wouldn't have ended up in? What if having a buddy makes a particular diver more complacent, or more willing to enter into a risky situation, or wanting to "impress" their buddy by doing something foolish? What if by solo-diving a particular diver becomes more adept/proficient thus increasing the likelihood he can assist a buddy should an emergency arise while buddy diving? What if a new diver is such a "natural" at diving that solo diving, for them, is no more risky than two new "lousy" divers buddy diving? Is mastersniper, for example, such a diver? I don't know, I've never dove with him...but I think it is a mistake to say that, across the board, no-one, as a novice diver, is sufficiently competent to safely and intelligently solo dive.
Also, who are you to determine what level of risk a particular individual should find acceptable? There are people who will say the risk of diving, period, isn't worth the risk. Have a buddy/don't have a buddy, calm water/choppy water...a number of people will say it doesn't matter-too risky an endeavor, period. But obviously for people like us (and millions of others) the risk is worth the reward. Likewise, the risk of solo diving can be worth the reward to a particular new diver, even if you don't think so. Solo diving for a new diver is risky, but a cave diver is probably more at risk for death than a new diver is when that new diver is diving in a calm OW environment. Cave diving has the highest fatality rate of all the certifiable diving disciplines, yet divers regularly embark into this realm. If "statistics", or "likelihood of catastrophe" is the issue here, then you should regard all cave divers as stupid for deciding to cave dive (even with proper training) because that training still doesn't do away with the high likelihood of death. The beauty and solitude caves offer is, to some, so appealing that they will venture into them despite the amount of risk involved. So too is it the case that some new divers will venture into the water alone because the draw is so powerful. My point here is that there is no inherent benchmark for "acceptable risk"...it's something people have to figure out for themselves. Like I said in a previous post: all one can do is provide a particular individual with information and allow that individual to make the decision for themselves...even if it's not one you agree with.