The National Federation of Independent Businesses, National Retail Federation and National Restaurant Association all operate on the premise that none of their workers will ever be their customers. Customers, they assume, are magical creatures who come from a world in which no one works in a store, or a restaurant, or manufacturing, or the service sector, and so keeping wages lower than low only cuts costs and couldn’t possibly affect demand. And now these poor lobbyists can’t figure out where all their customers have gone. It’s a puzzlement.