I have a Persian and in the 10 years I've had him he hasn't had ANY health issues. So that's BS that they "suffer" for looking like they do. Persians and beautiful, sweet, loving, laid back cats. The Exotic Shorthair - created in the 60's by crossing the Persian with the American Shorthair - has the same temperament. I have one of them as well. Incidentally both were adopted from shelters as adults.
As for the Munchkin I do NOT condone the breeding of dwarfism in cats. Breeders claim they don't have issues but since people think these cats are cute there's lots of bad breeders out there trying to breed for dwarfism that don't know what they're doing. The results is kittens with LOTS more defects than just dwarfism. Just look at "Grumpy Cat". The mishapen face wasn't just a birth defect the people who own him INTENTIONALLY tried to breed cats with dwarfism.
You also need to realize that less than 3% of cats on this planet are a breed and pedigreed kittens tend to be sold altered. So shelters aren't overflowing with cats of particular breeds they're full of all the no breed cats from random breedings. 99% of the cats you'll see on petfinder.org labeled "Russian Blue", "Maine Coon", "Bengal", etc are just domestics mislabeled by clueless shelter staff.
As far as dogs go well dogs were all bred for a PURPOSE while cats were just bred for a LOOK. Cat breeds have only been around for a hundred years or so - some are just a few years old. Many dog breeds, meanwhile, have been around thousands of years. I have a Newfoundland and it was bred as a dog to accompany fishermen in Labrador and Newfoundland, Canada in the 1700's. Other dogs were bred to work with hunters, to guard homes, to get rid of vermin, etc. There are also the "Toy" and "Nonsporting" breeds which, like cat breeds, were simply bred for a certain look at to be human companions.
The only fault I see in reputable breeders of dogs is that they are always sold unaltered. Unlike cats, altered cats can't be shown. But since the majority of dogs being sold by kennels are either not show quality or if they are, will never be shown I really wish they would alter at least the pet quality puppies. If they did then we certainly wouldn't have so many of these backyard breeders breeding mutt mixes like "Labradoodles", "Maltipoos", "Puggles", etc since the only unaltered puppies available would be the pricey show quality ones.