I think a big part that people are leaving out of the equation is the source of the fish. The only LFS near me when I started reefing sold fish that looked okay on first inspection, but once they came home had a poor rate of survival. I ordered all my fish online back then, while my friend primarily bought at this LFS. I don't think I ever had a single casualty with my online fish, while my friend had nothing but problems with fish from the LFS. He probably had casualty rates above 50%. If I was in my friend's shoes and didn't have a point of reference, I might have assumed that I was killing the fish with improper QT. The reality is the fish that this store sold were likely just unhealthy. My friend wasn't an expert, but I saw his QT and tank setup, it was all pretty standard. We were both basically doing the same things, but his fish were dying and mine weren't. My sample size is small, so take this anecdote for what it's worth, but it's still a good point to consider.
Fish are a lot more hardy than we give them credit for. They can survive in some pretty poor conditions. I'm not advocating that we intentionally keep fish in unsafe tanks, but if you're following any one of the basic QT stickies on the forum, your QT tank is not killing your fish. They were sick to being with, even if you couldn't see any external signs of problems. When people go to the hospital, sometimes they die. That doesn't mean the hospital killed those people (unless the hospital is unsafe or has problems with secondary infections, but that's fairly rare in the US). Those people were already sick when they went to the hospital, or they suspected they had an undiagnosed health problem.
