You don't need to keep all of it working. Most of it can fall apart. During the decline, important things will retract, move around, be protected. Look at what happened in the Holocaust. European Jewish culture wasn't wiped out. It was dealt a massive blow. Many important things were lost. But the community closed ranks and certain assets were protected too.

This apocalyptic thinking is something you only do if you're so removed from violence that you have to imagine the whole world ending to conceive of it getting to you. People who actually deal with violence know they never get all of us. People are lost. It sucks. But we are resilient too. In a million people, there are always a few who are both smart and lucky and are able to reorganize reality ahead of the wave. That's why there are 6 billion of us. We survive.