The souvenir booth at the 2009 Coachella Valley Music and Arts Festival said it all. At one end, a T-shirt was proudly exclaimed: “I’m here for the opening bands.” At the other end, a collection of merchandise was printed with a single name, “Macca.” Most of the 43 acts in Friday night’s lineup were buzzworthy indie artists. But topping it off was one of the most commercially successful musicians of all time: Macca
