I've worked at various vets and humane societies back East and I can explain why they all stick to dry food. It's because it can sit for days, it doesn't attract flies, it doesn't stink, it doesn't make for so much stinky poop, so it is a lot less work for the staff. It saves time and time is money. I volunteered at one big humane society and they actually threw away all the canned food they were donated, they wouldn't even bother to phone some other cat shelter to see if they wanted it. Since the research shows that wet food is better for the cats (and I can tell you that the cats really really appreciate it and are much happier), what else but this explanation fits?