(See: https://qz.com/807419/is-it-even-possible-to-sell-luxury-on-..., among other articles that you can find from googling.)
But I agree that it's very strange that Amazon is buying Whole Foods, which is a luxury grocery store, to then try to replicate Walmart. This will just alienate the customer base and drive them to Traders Joes, Coops, etc.