I've been giving this some thought, and I think it is a lot like the housing market and buying a house and obtaining a mortgage. (and by extention, what led to mass foreclosures and a sinking economy is the same principle that has brought us an overpopulation of dogs and overcrowded rescues)
When you go and purchase a house, you have to look at houses, establish a budget, save a downpayment, inspect the home, apply for a mortgage, sign a contract, make an offer... it's a long process and we don't expect it to be easy. We also don't expect everyone to be able to purchase a house. We don't expect everyone to buy a new house, either. (in fact, most people don't. They buy already existing homes. Well, until about 1996, that is) But are you going to buy a house without knowing what kind of work it will need? Would you buy a house based on appearance alone?
When shady lenders (with the encouragement of the government) loosened lending requirements and made sub-prime loans to people with less saved and a history of not paying back debts, things went wrong. People bought beyond their means. Sure, some people have not had any problems paying their mortgage on their small income, but many, many people did. Now we are in a mess. We have too many homes and people can't afford to continue living in the ones they had.
People thought they deserved a house at any cost, and there were unethical people out there willing to give them the money.
Like houses, people want dogs. Nothing wrong with that. You can take time and look for the right breed (like looking for houses), find a breeder, ask questions, get health guarentees (similar to a home inspection, in a way) wait for planned litter, place a deposit (down payment) on the dog, sign a contract, and let the breeder pick your dog based on your needs.
When people got impatient, other means were developed that are, in some ways, sinister. A backyard breeder is probably more like the lender who is just excited that they can sell to more people and make more money, where a puppy mill is more like the shady lenders who sold poor people expensive loans. (to extend the analogy, I think of rescues as the equivelent to renters, "oops" litters the equivelent to buying a fixer-upper in a marginal neighborhood, and a reputable breeder like purchasing a new or existing home in a desirable neighborhood of your choice.)
Of course, people need a place to live, so they rent, buy is less desireable neighborhoods, purchase from friends or family. People also get dogs through friends, "oops" litters and rescues, but if you want a new house in desirable neighborhood, you have to take the right steps. If you want a purebred dog to raise from puppyhood, one should take the right steps.
The biggest difference is that a house is a HUGE expense and a dog is pretty small in comparison. But both will have problems down the road, are investments (whether financial or emotional) and should be obtained by putting thought and work into ones decision.
This is long, but I hope it somewhat makes sense.