I can’t stop watching a certain video of Leon Rose. The New York Knicks’ president, a stout, taciturn man, surly about the mouth, who spurns engagement with the media but whose competence no contemporary Knicks follower can gainsay, stands in a crowd, surrounded by cheering fans. He’s in Cleveland, and the Knicks have just finished their Game Four rout of the Cavaliers—Eastern Conference Finals sw...