The major reason not to buy -- supporting the industry
You may wish to "rescue" a pet shop puppy. That's completely understandable. We all feel sorry for them.
But your good intentions will backfire, because you are feeding the industry by rewarding it with money.
You've emptied one cage, yes -- which creates demand for yet another litter to be produced to fill that cage. Even if you're very, very lucky, and your one individual puppy turns out okay, a large percentage of the others will not -- and YOU provided the incentive for them to be born by buying the one who came before them. YOU SUPPORT neglect, abuse and animal cruelty.
So what seems like a simple, isolated purchase actually contributes to:
• The misery of adult females who spend their lives in a cage, being bred again and again to provide puppies that you and others can buy
• The misery of these future puppies born with health and temperament problems
• The misery of future families who buy these puppies and then try to cope with the health and temperament problems
• The misery of animal rescue groups trying to deal with the flood of pet shop puppies dumped on their doorstep because families gave up on the health and temperament problems
When you buy one of those cute puppies in the pet shop window, you buy more than the puppy. You buy the budding physical and behavioral problems created by the bad genes passed on by untested parents whom you never get to see and evaluate.
Worse than that, you buy into a profit-hungry industry that is hurting innocent animals. Simply out of good conscience, a pet shop should not be anyone's choice as a source for a puppy.