In order to survive an apocalypse you must first watch most of the world's population die. Then you have to live while avoiding death from hunger, disease and monsters; the human variant, the used to be human variant, and the fantasy type monsters with claws, fangs and blood covered teeth.
Without the changes made to the world there was no way Desmond Slattery would have made it through his first civilization ending event. He would have died early on if he hadn't started leveling up, Post-Apocalyptic RPG style!