Perhaps I didn't make this clear. "Accidental" solo divers are not accidental. When you lose your buddy, good buddy skills call for looking for your buddy for a minute or two, then surfacing. If you continue the dive, then you are a solo diver - regardless if you have the training or equipment.
I think that the scenario that you laid out is laughable. Your reference to any diver as an "oaf" makes me wonder about your attitude as an instructor.
As far as I am concerned the SDI solo cert simply institutionalizes arrogant and self-centered behavior that has no place in diving. Diving solo because it is more convenient is not a good reason to do so.
The first thing that I learned about diving is that there really aren't any rules. While a PADI OW card "limits" you to a max depth of 60ft, it is a recommended limit. There is nothing preventing you from going on a dive and going to 80ft or even 165ft... on air. The risks that you assume are your own. In a way, we, as a diving community, respect this individual right to do what we want. But this emphasis on self-sufficiency is taken too far.
On a recent dive, I didn't notice that hoses were tangled up, nor that I had a slow leak. My buddy immediately let me know that I had a problem before the dive started and the problem was simply and quickly resolved. Let's say that the o-ring let go at depth. Then, as a solo diver, the plan is to go to your pony bottle and surface.
But now you're task loaded and pretty stressed out. Perhaps everything works as it should, and you surface without a problem. Perhaps you have another problem. Perhaps you've had an off day and you make another mistake. Who knows?
Why bother? My buddy saw something that wasn't right and we addressed the problem before it became a serious issue underwater.
And I find this consistently. When I dive with buddies with good buddy skills, the dive goes more smoothly and I'm able to concentrate on the dive. If something does go wrong, I'm confident that my buddy and I will solve the problem together.