Luxury canned tomatoes

Quick question: how is an increase in profits at Whole Foods indicative of a rise in "luxury shopping"? Yes, yes, "Whole Paycheck," but it occurs to me that any supermarket, however snooty, is an alternative to dining out. I can't speak for all the locations, but the NYC and Chicago ones tend to be a) in areas where supermarkets generally are kind of posh, and b) where there are lots of restaurant options for restaurant-inclined yuppies. Maybe people who used to buy groceries at Walmart have upgraded, or maybe, just maybe, the yuppies are just cooking at home more, which would if anything indicate a decrease in yuppie self-indulgence.