Another thing I should add for BW, is that regarding the whole debate people bring up about BYB, puppymills and rescues is that you aren't that likely to find even a purebred in a shelter or rescue that was properly bred. Yes, they may be pure however reputable breeders have a take back policy which means at any time in the dogs life, for ANY reason if you need to find it a new home or can no longer care for him/her, you are required by legal contract to return the puppy to the breeder to either be kept by them, or found a new home. People who are aware of the BYB/puppymill situation usually do not going looking for a reputable breeder puppy and then surrender it to a shelter. At least I hope most wouldn't.
So in a lot of cases, BYBs and puppymills are the cause for the need of shelters and rescues (that and stupid owners) yes, but as said, the more people go to the source of the problem, the more the source will keep finding a reason to stay around, increasing the need for more shelter and rescues, decreasing the availability for all dogs or cats to have homes, etc. It's a supply and demand thing really. BYBs and puppymills are aware the most of the world's population just "want a dog" and so they make a supply for them and do it in such a way where it seems more "convenient" to the buyer. Reputable breeders screen for the right owners, BYBs and puppymills screen for the right dollar sign. The same with pet stores.
While some rescues and shelters do get puppies or kittens in, you'll find a lot of their population is dogs that have passed that age because they weren't "cute" anymore, or someone didn't realize how much work and responsibility goes into raising and properly caring for an animal. I still believe that I think a new requirement to apply for a license to own an animal would curb a lot of issues... "I want to buy one of your puppies Mr. Backyard Breeder." "I have to ask by law, where's your license?" "Um..." "Come back when you get one." *kid leaves* "This isn't worth the trouble anymore...I quit." *animal lovers rejoice*
