Variety: The parlor-room drama surrounding the fates of Viacom and CBS has only reinforced how thoroughly Sumner Redstone has exerted control over his media empire for decades. And Rupert Murdoch’s succession plans at 21st Century Fox and News Corp. has all the intrigue of royal-court maneuvering among heirs to the throne held by an iron-willed king. All those companies are publicly traded entities, but their respective boards and shareholders won’t call the shots when the time comes for big decisions such as succession.