“If people cannot afford to shop at WalMart, this is really, really bad.”
You can add McDonald’s to that list.
The problem with McDonald's doesn't seem to be affordability or prices -- rather, competition & changing tastes. People nowadays, especially the young, have more options, and they're all gravitating to tastier or healthier fare.
Not that I'm an economist; there are probably a lot of things going on that are way over my head. I have no real answer. However, it seems recently that a lot of these venerable places are imploding.