I agree DA/SA is a solution to a nonexistent problem. There is very likely no one here who has sent as many .45 down the pipe as I have. I haven’t had a contaminated primer yet in my life, but the man who can fire the first shot DA, then the second one in .3 seconds SA accurately is a special 1 person indeed. I have shot about about 200 rounds a week through a .45 ACP since about 1974, winning lots of speed events, mostly with an Ed Brown modified Series 70. typically the second shot is going to go off before you’re ready, then you are so rattled the third is a waste as well. I can shoot a DA revolver, so would much rather have DA only, a Glock type action or SA only. You don’t need anything else on your mind in a fire fight. In that rare 1 in 50,000 rounds bad primer, the military won’t train you to pull the trigger again, and wonder whether it will fire, work the slide and get it out of there and take your chance on the next one. By the way, I have serious doubts if a primer is oil contaminated, that another strike is going to do a damn thing, except get you shot when it doesn’t go off. Clear your weapon and fire a fresh round.
As my little girl would say: "that's about a million, billion, thousand, five thousand!"