
I think you will find many urban puppy farms, though the isolation of a rural environment makes the puppy farmer less visible or should I say hearable.
Unfortunately the commercial production of companion animals is seen by the authorities as a perfectly legitimate business.
Most good breeders will contend that you cannot breed and rear (emphasis on rearing and socialising) puppies commercially as they require a lot of time, and this cannot be done on a wholesale basis with lots of litters at any time, and you cannot make money if you do everything in the best way. Choice of breeding animals health testing proving their quality by showing and working etc.
So commercial breeding can only produce substandard under socialised pets. though sadly many one off litters bred by people without the knowledge and care required can produce just as poor quality, and not be breeding commercially.