Alec Torres writes for National Review Online about the fallacy of asking all retailers to emulate Costco's high wage, low turnover model. It turns out Costco can pretty much sell their wares at cost since most of their profits come from pricy annual membership fees.
As Torres points out, not every store can operate the Costco model. Many consumers cannot (or will not) pay membership fees for the privilege of shopping at a store.
On the other hand, are you tired of looking at fellow shoppers in other big box stores and noting they come from the shallow end of the gene pool? Costco's fees may be a worthwhile price to pay to avoid this angst.