that's not entirely true. for instance, if you're a vegan on a subsistence diet (tortillas, bulk beans, etc.) you can get pretty good stuff for competitive prices. not as cheap as spanish harlem, but far from crazy.
i just found some high-quality generic coffee beans there the other day for $5.70/lb., which is about the same price as Folger's swill at a regular supermarket.
but overall, yeah, they mostly sell 60th to 80th percentile quality stuff for 99th percentile prices. i was amazed at how mediocre Whole Foods really was, at least compared to specialty shops which are usually a bit cheaper. still, if you're in the middle of nowhere and a Whole Foods opens, you suddenly have the option to buy nice things. i can see the appeal.