Hunting, especially handgun hunting is about sport. Sport, and ethics. I have no issue whith someone choosing a single shot for that. I have them myself. And I don't have an issue with someone who uses a single shot asking why single shots haven't "killed off" repeaters in the sporting market.
Because it is a valid question, and it has an answer. The answer is that majority of the market wants a repeater. And that is because while the object is to shoot well enough that the animal is DRT, reality steps in, and that means, no matter how well we do our part, and how hard we try, sometimes things just don't go the way we would like.
but one of the few truths I have stumbled upon is: When hunting, if you miss your first shot, you have little chance of taking a clean shot on an immediate follow up.
Quite true, when hunting with a single shot. With a repeater, you have an option you don't have with a single shot, the option of an instant, or fast follow up shot.
When you shoot a game animal, you have a moral obligation to ensure the animal is dispatched as cleanly and humanely as possible. TO me, that includes a responsibility to do everything you can to ensure the animal does not get lost.
My limited experience has taught me that if the animal doesn't immediately go down, "DRT", it is best just to let them run a little, settle and die, then trying to shoot as they run.
Sometimes, this is the best course of action. But each shot is different. Terrain and the reaction of the animal are big factors in making the best decision. If you are hunting in thick terrain, letting the animal run a little, settle and die might mean you never see that animal again.
Sure, shooting running game is difficult, but that doesn't mean it is non-sense. It is very much a matter of the abilities of the hunter, and the specifics of the situation. What is the right thing for one person is not always the right thing for another in a different situation.
Varmints are one thing, big game another, to me. I have tracked wounded game. I have seen wounded game lost, despite everything a party of several hunters could do. To me, that is a failed hunt. It's not a good thing, and I was taught to take every advantage I could to see that didn't happen. And that includes any follow up shot that offers itself.
I have seen many cases where a fast follow up shot made all the difference. I respect the single shot hunter, for the limitations he voluntarily puts on himself, paramount of which, in my opinion, is not shooting when one cannot be certain one shot will be enough.