I don't have any problems with putting new blood into an old stagnant purebred gene pool. IMO, no one should have to pay money for a dog, the most that should be payed is just a slight adoption fee...this would cut back on overpopuation and breeders breeding horrible unhealthy dogs. There would be no profit for anyone to breed. Look at our cats, the ones that suffer from disease are the purebreds, your regular cats (normal, or in the dog world they would be considered mongrels are healthy).
There is no such thing as a "pure" bred dog...all dogs come from ancestors of mongrels and mixed heritage...the only difference that set them apart are at one time is how they naturally evolved to suit their environment. You would have had livestock gaurdian dogs, border collie type dogs, mastiff type dogs...not purebreds just types or as some may say Mongrels. So, some people may argue that a certain breed has been around for hundreds of years, this is false...what they are seeing are natural types of dogs that basically had the same name...but, these dogs did not have a breeding program and just naturally evolved without the help of man. Natural selection is much healthier overall for a race of dogs.
Purebred dogs are fairly new, and when you think of it purebred breeding promotes inbreeding...you have to inbred to create a purebred dog, and you have to inbreed and line breed in the future...there is no other choice especially with most breeds coming from very few founding fathers. Say for instance (this is just speculation) when they brought the Siberian Husky over here to North america...they started out with about 6 dogs, all of our current Siberian Huskies would come from these 6 orginal dogs (except for responsible breeders who knew how horrific a closed stud book could be and crossbred their siberians and lied to the kennel clubs, that happens...some breeders know how unhealthy purebred breeding is). So, if some one asked me what do I think is more healthy I would definately say crossbreeding is healthier than purebreeding. How shallow we people can be when we become so obcessed with how a dog looks....and quite frankly we don't have the need or jobs for purebred breeding as we did at one time when our dogs actually worked for us. Even when they started simular breeding (planned breeding) a couple hundred years ago they were not exactly keeping purebred dogs but types of dogs...they didn't even care who the father of the pups was just the mother as the pups would learn all the required behaviors and job from her.
Just my opinion