Ah, but here is the best part - if the pet store doesn't sell a puppy within a certain period of time (they all have that window of opportinity, at the close of which the puppy finally reaches an age believed to be beyond sellability - in other words, they reach their 'expiration' date), most of them are turned over to local humane societies and shelters for placement/euthanasia. The bulk of these older, 'unsellable' puppies are extremely poorly socialized and in poor health, granted, but they are released from the pet store to at least somewhere where they have a half a chance beyond the pet store. And the more the pet store has to get rid of like that the less money they are making on live pets and the less apt they will be to keep live pets.

There is no disease that does not have a cure, and puppy milling is a disease of the blackest sort. Sometimes it takes a while to get there, and some have to suffer as a result, but aren't the sacrifice of a few worth the later salvation of all, given that saving those few result in a continuation of the abomonination of puppy milling?

Yes, it is a hard attitude to take over the lives that are lost as a result of the pet store being unable to sell puppies, but if the demand does not exist the supply will eventually stop (or at least weaken to a trickle).