MTV turns 40 this Sunday. Did any adult child not named Lizzie Borden ever disappoint the parents more than the three-letter network? “We’re the reason you have no attention span,” original VJ Mark Goodman quips in VJ: The Unplugged Adventures of MTV’s First Wave. “And you can pin reality TV on us too. You’re welcome.” Yet, those first years were glorious. From “Video Killed the Radio Star” as its prophetic opening to the evangelistic “I Want My MTV” crusade to spread the good news upon recalcitrant local cable companies to its giveaways of a little pink house, a lost weekend...