Peter Culshaw thinks he knows: “The real problem seems to me the disappearance of spontaneity and fun from the world of jazz. Marsalis’s attempt to turn jazz into America’s classical music often produces work that is respectable and bourgeois to the point of dullness. Yet take a look at the greats of jazz history, from Fats Waller to Billie Holliday and Miles himself, and you will nearly always find a sleazy undercurrent of sex and drugs.”