Beds for pets? No way. My dogs and cats are perfectly happy sleeping on any old rags. They are even happier if I give them some of my old clothes. Apparently the smell of me on my old clothes is pleasant to my pets.
Of course, this does not stop people from buying such things for their pets. I think the main reason is that they are brought up to believe that the more money they spend, it proves that they love their pets even more. Probably such people would do the same thing with their own children, too. Like buying expensive toys for the children without thinking whether the toys have any kind of educational value at all.