Joe B. WallI contend that postapocalyptic settings for fiction are pretty much like all Disney's characters with dead parents, most works set in a "multiverse," and sci-fi set in either the far future (looking at you, Dune) or in a simulation in being a suspiciously convenient way of solving the problem of being a bad writer who can't tackle complex human interactions or the chaos of history. Kill everyone off and those pesky complicated relationships won't trouble your narrative!