Why not? At the risk of sounding like a hand-wringing capitalist, at the end of the day, isn't the purpose of a business to charge money in exchange for providing a good or service that is useful to a customer? If Starbucks can greater serve the needs of their customers by providing a new item (regardless of where they got the idea from), then why shouldn't they? Some might argue that they are actually doing their customers a disservice by not providing it and making them go elsewhere.