The Great Depression had a long disaster to normal return time.
The Rodney King riots had a very short return to normal time.
And that frames the issue of how long you need to be prepared to survive after a disaster. Either you are completely unprepared, prepared to handle a short term disaster, or prepared for a longer term disaster.
But what do you need to survive? It breaks down into knowledge and resources. There are a lot of people who have one or the other, but not a lot of people have both. Having a lot of one can make up for a lack of the other sometimes, but that is not a good strategy to have.
Having the Army Survival Handbook in your library won't do you a lick of good if you haven't read it, and if you have read it is you can't make safe drinking water without the plastic sheeting or poncho needed to make a simple solar still. And do you really want the first time you make a simple solar still to be when you really need it to work?
I think that I will have to make a note to practice some survival skills next camping trip. Carving out figure four traps and making a solar still will top the list. Not that I need those skills to survive a short return to normal span of time, but because it will make me think about what I do need to do to survive for longer periods of time. I know that I can starve for a few days and be just fine, even walking with a heavy load on my back for long distances. But I have to figure out how to deal with the longer than a few weeks of survival issue. If I couldn't leave my home due to a quarantine I would be very dependent on the water utility continuing to provide water.