We're in the same ball park, but if you think that MMA failing is the rule, even if there are exceptions, I think you're crazy. There is enough evidence to the contrary that I can't imagine how you think that. It's like pointing to cars that are up on cinderblocks as evidence that most cars don't roll down the street. We have enough evidence to see that reality is that cars that don't roll down the street are the exception, not the other way around.
Adding to MMA training some additional context is helpful. But to be clear, I'm thinking things like helping people identify high risk behaviors and avoid them, or having a conversation with someone about how getting drunk and picking fights is a bad idea. For most people, that's all they need.
But because there is a competitive element, MMA training has an inherent integrity. ANY competitive art will have an inherent advantage over ANY non-competitive art. And along the same lines, some training will actually make you less capable. Any art that lacks a competitive element is a crapshoot, because you think you know how to do things you may not be able to do.
I also think that the idea of needing to train "self defense" to learn self defense, is a little crazy, because "self defense" is an abstract. You might as well be saying, "If you want to learn leadership, you need to train leadership." Sounds fine in theory, but it's a functionally meaningless declaration. This is why I firmly believe that any discussion of safety has to be statistically supported. On an individual level, you might be lucky or unlucky. But on a macro level, if you're addressing a statistical need and measuring it accordingly, you will be able to gauge the success or failure of your training program. This is particularly true if you can go so far as to identify a control group.
Finally, I just flat out disagree that cops or anyone else who are professionally at risk are engaging in self defense. Or at least, that their self defense is relevant to non-cops. Don't get me wrong. A cop is probably among the most qualified to teach self defense, because of their experience. But what cops learn and what is helpful to a non-cop are not the same. I understand that others disagree with me, but I just flat out believe that a cop does not engage in self defense in the course of being a cop. They engage in risk as a function of their profession. In other words, being a cop, a bouncer, a security guard, a professional MMA fighter or a whatever else is a grounding that can inform training for a regular joe, but they are all different pieces to the puzzle.