In
Real Life, a lot is needed to produce, distribute, and maintain much of what we take for granted. Cars need someone to mine and process the materials for the parts, someone to pump the oil, and so on. Guns need someone to produce the weapon materials, ammo, and someone to put it together. Refined foods need a large base in order to be accessible to a large number of people. Even an object simple as a wooden
pencil needs all sorts of industry and resources to bring it together. (Someone has to get the wood, someone has to mine or manufacture the graphite, someone has to get the rubber for the eraser, etc.) And of course for all of these, someone needs to ship the finished product from one end of the world to another.
In short, if something were to happen to upset the system behind much of what we use in the modern world, production of and access to such things would be very difficult, if not impossible.
However,
After the End, the loss of the infrastructure that allows for all of this seems to be only an inconvenience for the characters, rather than the huge game changer it would be. While vehicles, weapons, and other goods tend to be
rusted out and made
from all sorts of scrap, they are only marginally less effective than their pre-apocalypse counter-parts, and finding the resources to maintain them is only a mild inconvenience at worst, or not even a thought at best. Sometimes, the work will even ignore the rusted out part, and pre-apocalypse goods will look no worse for wear than they were before the bombs fell and the dead rose from their graves.
Simply digging them out might even be the key to victory. This can be even more jarring if the work is set
generations after the fall, and the world is still at rock-bottom, yet finding
functional pre-apocalypse goods isn't too much of a hassle, and/or making post-apocalypse equivalents still isn't that difficult, nor are they that worse off compared to the former.
In many cases, an
Acceptable Break from Reality, because unless the main focus of the work is to look at the hardships the people in the aftermath face in getting modern necessities; it would be quite slowing on the pacing of the story to have to have segments that simply feature resource gathering and production. Can be
Handwaved in having it happen off-screen, or having the characters have access to an untouched remnant of civilization. Can be justified in the early years of
The Plague stories, in which the population was decimated enough to keep the infrastructure intact, along with any supplies therein. Of course, production of new resources would be another matter.