Are retail employees supposed to sell products or help shoppers? A retailer's lifeblood is sales and therefore every retail employee needs to sell products. Your retail marketing should be oriented to sell-through. But there is a difference in the answer to this question that results in a short term (sales) or long term (service) focus.
Apple's retail stores are as oriented towards service as they are sales. In fact, a quote from their training manual reinforces this: "Your job is to understand all of your customer's needs - some of which they may not even realize they have."
Said another way, your job is to help shoppers. And through that help, based on having relevant products, the solution could be a sale. But the employee's focus is not a sale, and as a result, Apple's stores provide a richer shopping experience.