Because there's a huge difference between the OP and actual responsible breeders. Responsible breeders don't breed to produce pets for the "market", and take back dogs they produce at any time - i.e. they aren't directly contributing to the shelter population. They title their dogs to ensure they are breeding quality specimens, and do extensive health testing to ensure they're not taking their breed backward.
My cats are from a shelter, but my dogs are from breeders... because I show my dogs in conformation and performance events. Rescue dogs can be great for performance, but in my breed there are several very serious health problems and I want to do everything in my power to ensure I have healthy dogs with the correct temperament. I have a wonderful breeder that consistently produces the type of dog I need for the activities we do.