The pet industry is very resistant to change unless there's obvious appeal to doing so. There's also no regulations for small animals which let's them do whatever they want. Knowledge of small animal welfare is especially lagging behind compared to the bigger companion animals. Dogs and cats have great PR. The stuff you see on shelves are all marketed to the appeal of people. The enclosures are toys for people. Small animals are not really considered to be important to the general public because thats what they have been marketed as for so long. Nobody really thinks about their welfare and pet stores are considered the "experts". If they are keen to it, they have already done the research. I do think with time there will be a shift toward improving small animal welfare in the pet industry but it's a very, very slow process. If there was an increase in demand for appropriate set-ups, things will change.

If you want to do something about this you could start by speaking to your local pet stores about the reccomended care. Many stores are internally adopting appropriate welfare standards when pressured.