I agree, there are breeders out there who are registered that have massive numbers and should be labeled puppy farmers, I noticed however that you put in the section that large breeds make up 80%, but then you put in mastiff x, pitbull x, and then the kelpie x, all of these are cross breeds, not recognized breeds in their own right, and the kelpie is NOT a large breed. Why are large breed dogs so common in pounds, because they are stronger, harder to work, physically more demanding. The arguement of being pure bred or a cross breed is not just "they are all cross breeds at some stage", it goes much further than that too, pure bred dogs in Australia that are sold with pedigree papers are SUPPOSED to be held to a standard, not only standard of dogs, but also a moral and ethical standard. (Please note SUPPOSED) Not many pet stores will take on pure bred dogs due to the higher cost, why do they cost more? Simple, there are standards, if you want a pure bred dog you will be willing to part with more money, you are more likely to be thinking about your purchase and it wont be a spur of the moment purchase.
If you look at the stats in more detail, where do most pet purchases come from, it would have to be said that internet and paper ads make up the majority of purchases, it easier.
The argument against having pets sold in pet stores goes beyond dogs that are dumped, it goes into the overall welfare of the animals, you have seen threads on this forum, disgusted at the standard by which animals are housed, as a dog breeder we do not lock our pups into a small area 24 hrs a day with no access to fresh air, nor do we run them on shredded paper, only a select group of people get to view the pups once they have applied to us to be able to own one, not every Tom, Dick and Harry walking past tapping on the glass. Many pet purchases from pet stores are spur of the moment, I went in for......and came out with......Many pet stores do not have the adequate knowledge of what is better for the animals, only what they can shift. I avoid the pet stores with live animals for this reason, I will go to ones who sell product they not only recommend but also use themselves. If you look again into pet sales, most pet stores make money selling fish, this is due to the fact there is a lower moral code of ethics, its just a fish, no emotion, no feelings, so every pet store seems to sell them, they are cheap, easy to shift and can be sold off as low maintenance with all the new gismos on the market that allow a person to only have to worry about them once a week or so, just feed them and change their water occasionally and they will be fine.
Unfortunatly reptiles in pet stores are a problem due to the large number of stores (in Victoria) that actually have no idea of the proper maintenance of reptiles, what requirements they have, that arboreal species need to climb and terrestrial species need more land space. Again the store often does not sell a person what they need, but what the store needs to shift. They will sell product that is overpriced (Top of Decent $34 per can!!!), give poor back up support and generally the staff lack the knowledge to understand the animals.....I have been into some with great reputations and asked to be shown their tortoises, only to be shown turtles, told that there is no difference between a turtle and tortoise and that while DSE use the common name eastern long neck tortoise then that is what they are........(so does that mean a king brown really is a brown snake???) In Queensland the sotre has to undergo training, but once the people who have done the training leave, the store still keeps on selling the reptiles with little to no knowledge of the animals that they are selling.
Overall pet stores selling live animals should be held to a much higher standard, regularly checked on and real penalties applied for breeches of conduct, and tomorrow pigs will fly too!