You might think of a big Broadway musical, the next show, as the next generation of an iPhone. Each production builds on the achievements of its predecessor and, if the creators have been successful in filling the needs of their audience, they start out with the kind of huge advantage that beats back competitors. So, for example, Richard Rodgers and Oscar Hammerstein II had the benefit of "Oklahoma!" when they wrote "Carousel," and the benefit of both of those masterpieces when they wrote "South Pacific," and then "The King and I." Each time, they were growing older and wiser and refining their technique. Just like Apple with its new phones.