But HBO’s TV series, along with “Avengers: Endgame” and “The Rise of Skywalker,” are coming to us at the end of an age that has sustained our imagination with tales of magic existing in the world of the mundane as epitomized by the “Harry Potter” series. In many homes J.K. Rowling’s books share shelf space with chronicles of terrible futures wrought by ecological degradation and greed, as in Suzanne Collins’ “The Hunger Games.” Dark as each of these books series could be, if light didn’t eventually prevail . . . well, they never would have become cinematic hits. Nobody wants to invest in a multi-part saga that leaves us moping as we exit the theater.