The thing that most people miss about apocalyptic movies like any zombie movie, Water World, etc--is gasoline.
Gasoline degrades much faster than you'd suppose. Within a year of the apocalypse, nobody's driving anywhere.
https://mechanicbase.com/cars/how-long-does-gasoline-last-in-a-plastic-container/
My lawnmower gas that sits in the shed for a year says otherwise!