That's because breeders don't often look out for what's best for the fish but what's best for their pockets. Most fishbreeders inbred their fish to get a certain trait. If you want a purer or truer fish you gotta go with wild caught.
Wild caught fish are usually more healthy but I've others usually are easierto breed in captivity. If the fish are difficult to breed I wouldn't buy them wild caught if someone breed them.