Most people are quite okay with hamsters, guinea pigs, rabbits, and birds being confined almost exclusively to a cage for their entire lives. This is probably so, because none of those animals are typically considered to be mankind's best friend. On the other hand, pet ownership of dogs and cats has never been higher and while a well-adjusted cat typically does their personal business into a litter box, a dog does not. There is also the additional advantage that most cats have over dogs which is that they are physically smaller than most dog breeds; so that, in short, cats therefore are not often caged, though some are restricted to only certain parts of the house or restricted into entering into certain areas of the house. Whereas, for dogs, with very few exceptions, they are naturally going to have to take care of their personal business outside, though there are, regrettably, alternatives to that, with potty training pads being available for dogs. So too, while it is not unusual for someone to describe their cat as an "indoor cat", it seems to be an oxymoron to state that one's dog is an "indoor dog," yet, many dogs are treated as if that is the case.
Nowadays, more and more people have cages or crates inside their homes, typically used to cage their dog during their absence during the day, of which, many of these cages are so small that a dog doesn't have much choice except to lie down and not all that much room to turn around and move. These are, quite frankly, very confining to a dog, with some people, even experts stating that cages for dogs are a good training tool as well as being acceptable, for dogs are "den animals" and confining a dog for hours during the day is fine, considering that dogs do an awful lot of sleeping.
The biggest problem for those that are proponents of dog cages, or for those that believe that dog cages are an acceptable solution for a dog that will possibly chew up and be destructive while alone, or will poop or pee all over the house, and so on and so forth, is the solution to the "problem" doesn't seem to have properly taken into account the responsibility that the dog owner has to the dog, to begin with. That is to say, dogs are social animals, and they do require walks with their owner or a responsible party, in addition to just having social time with their owner, and therefore long periods of separation are not beneficial to dogs, so that, being confined to a cage which offers none of the accouterments or space that might help to settle that dog down is cruel.
There are some people that are not in the right place or maturity or responsibility in their life, to be a good dog owner, yet, they own dogs. The least that large conglomerate pet stores could do would be to educate dog owners and to provide viable alternatives to cages, of which, a reasonable alternative would be to have an enclosed space, such as the family room, that has a gate attached to it, that keeps the dog confined within that area but still allows the dog to actually sniff, look, and move about; as well as all other devices or alternatives that are more humane than a very confining cage, including a fenced back yard.
Those that currently cage their dogs, need to see such caging, as a very poor choice, and should endeavor to find something that is more natural and fairer to the dog, along with making it a priority that when they are at home, that they will socialize with as well as walk their dog, because a best friend surely deserves so much better than just being caged.