If there was any debate about “Succession” creator Jesse Armstrong’s place among the upper echelon of television storytellers, Armstrong snuffed it out by declaring the show’s fourth season would be its last. In interviews with Armstrong after he announced his intention to go out on top, he talked about how the show’s title is a promise to the audience. For “Succession” to have real stakes, Logan has to decide, finally and definitively, which of his silver-tongued, sharp-elbowed children is most prepared to assume his throne. It bodes well for the final 10 episodes of “Succession” that Armstrong understands the limitations of constantly reshuffling the same deck. Because in a show in which every character is after the same prize, the prize becomes just another MacGuffin, even when it’s a multibillion-dollar media and entertainment conglomerate. Given Logan’s rapidly deteriorating cognitive condition, a decision needs to be made sooner than later, as much as Logan would prefer to use the promotion as a psychological cudgel against his children for as long as possible.