Well the sad answer is that some people just don't care. Out of sight, out of mind. They don't realize the horrible conditions the animals are subjected to, the unsanitary conditions, the diseases, the violent treatment of the people who run puppy mills.
In Canada the Humane Society and police work continually to find puppy mills and shut them down. Dogfighting and cockfighting activities are similarly banned. In Ontario the penalties for persons guilty of such offences can vary from $1,000 to $60,000 with possible imprisonment of up to two years. Learn more by reading the Ontario Animal Welfare Act.
A puppy mill's primary goal is to make money. Regardless of what price they set on selling these pets (often sold via pet stores with dubious reputations) their goal is to make as many pets as they can in a hurry in an effort to maximize profit and very little overhead.
We won't go into the details of some of the horrific treatment cats and dogs endure at puppy mills, but we can show you a few photos of animals which have been rescued from puppy mills by the Humane Society.
"Don't ever buy a dog unless you have personally visited where the dog was born and raised."
Now you could buy a rescued animal from the Humane Society... but buying any pet which may have been subjected to violence is risky, especially if you have children. Abused animals can sometimes respond violently without warning.
No, its far better to buy a pet from a dedicated breeder. It may cost you a lot more money, but over time it will be a wise investment. ie. Toronto Maltese Puppies cost $2,000 to $3,000, but over a 10 or 15 year period the financial sting isn't so bad. Especially as you grow to love and adore your pets.