Being an obsessively care oriented person and having worked for a brief time in a tiny fish shop, I'm so glad you took the brave risk of pointing out the "other side of the story", Morgan! Even in small shops, the daily chores, always "interrupted" by customers, makes even routine things difficult. Even more so dealing with sick fish. One thing you didn't mention along these lines is that a lot of the fish deaths and illnesses are down to the way they were transported...esp if from long distances away or traveling in extremes of temperatures and sitting on the tarmac or shipping trucks! Then there's also the almost physical impossibility of having quarantine tanks, no matter how much you'd like to. Finally, I'd also like to mention on your behalf, and for others' consideration, that large box stores have no monopoly on bad fish husbandry advice! Nor do all mom and pop shops always provide good advice! Actually, I have received equally good advice from either; what it mainly comes down to is researching on our own first, before we even buy any dry goods, much less actual fish....then talking to several staff. That way you can get a really good feel for who seems to be most knowledgeable and try and stick with that person. You also might have something new and valuable for them to learn, which I've found almost every one of them was at least willing to hear, if not actually put into practice. The only way we can improve fish husbandry on a large scale is to stop making broad, preconceived generalizations, and work together and share knowledge. May we be blessed in doing so!
The more I think I know, the more I think I don't know much at all!