The crux of this problem, though, is dive shops have no financial interest in self-regulating above the current "good enough" state and for instructors you're relying on individual will to be better than "good enough". This is the point Gareth and I disagree on the most. In the absence of financial incentive (carrot), and assuming no meaningful agency change, I believe reputation risk (stick) is the only lever we have to effect any measurable outcomes.
Instructors and dive shops that do want to better, will be better. Those that don't, won't and will continue to kill people. Those that do want to do better will only benefit from transparency of these incidents.
The scuba industry is faced with an issue of poor personal judgement and lack of enforcement. The universal example of the success of checklists is only effective if there's some form of checklist enforcement. The enforcing agencies in scuba diving for the most part, have no desire to do such, so we rely more and more on personal judgement.
So now we're back to changing human behavior to make people want to do better. And to do that we can use the classic choices of positive reinforcement, negative reinforcement, or punishment. Pick your poison.
I agree with what you say, I also train students in very challenging conditions and have been doing so for over 15 years. Whether it be in a TX Mudhole or in 3000 ft of crystal clear water known for insane currents (Northern Red Sea).
When I used to teach for another dive shop, you took however many students the center gave you, standards be damned. The reason why they could do this was because as an instructor, it's your responsibility to make sure students are safe and NOT the dive center. When I had challenging conditions, I made the assistants stay on the surface and only send what I deemed was a safe amount of divers. If I could see 8 then eight got sent down. If I could only see 4, then they came down in two separate groups. They never got off the platform except for on Dive 4.
That's how I was taught to dive, and it's how I was taught to teach at the time, I thought that was the right thing to do, after all an Open Water Class was not a license to dive, but a "license to learn".
I used to read on Scubaboard, about instructors who actually "taught" people to dive safely and only worked with small groups because it's impossible to "teach 8 people how to actually dive" and I used to say to myself, "That's fine if you are independently wealthy and retired, but at 45 dollars a student, no one has time for that".
Fast-forward a couple of years, and now I am living in Egypt, and I am on the receiving end of "kneelers" in 3000 ft of water with swift currents, and it was an eye-opening experience to say the least. Since it was post Arab Spring when I taught classes, I was lucky to have two students and got used to working with small classes, oh yeah, I also got paid more for teaching in a third world county than I did in the US and that money in Egypt went much further, so I was definitely paid a livable wage.
After a second revolution, we decided to come home and open our own center, and I am ashamed to admit, I was in first place on that race to the bottom, using tools like Groupon to sell courses, after all that is what the certification agency recommended so it must be right. It took a biblical flood and a pandemic to get us back on the right path.
Now we train a max of 4 divers at a time, no matter what the visibility. We do hour long dives with them and teach them to love the mudhole. There's a lot to see if you know where to look and have great buoyancy. We even treat the grassy areas of the lake as our "coral reef" so they have to have good buoyancy otherwise they destroy a baby fish and turtle breeding ground and come out of the water looking like they have a gillie suit on. Our motto is, "the best review we can get, is from your dive guide on your trip". OMG do we get glowing reviews from them!
We also pay our instructors a fair wage for their time, and they get paid for a minimum of two students, even if they just have one. That was the standard in Egypt, and we brought that back with us.
We have actually caused other centers to do a better job, only so that can compete with us. Now I see lots of instructors doing longer dives with their students rather than platform bounces. So it goes to show that if you do a good job as an instructor, others will follow, even when they don't really want to.
So what does all this have to do with what happened at the lake? Nothing but, seeing all the comments about how teaching in poor visibility is an accident waiting to happen is completely false. I make far better and more confident divers in our lakes than I ever did in clear water.
From what I have been hearing on this post about the shop in question, this probably would have happened in clear water, but I am not here to judge without all the facts.