One key point that a lot of long term preppers make is that prepping with a LITTLE extra canned food is never a bad idea. Having the pantry stocked for a month, not a week.

It isn't about the survivalist fantasy of society crumbling into pieces over night, it is the idea of being prepared for those outlier systemic failures. A power failure for a few days, a flood, short term shipping delays etc.

As an aside, one thing they like to stress the most is, the single best thing you can do to be prepped is to be in as good of health as you can manage. If something goes down and you drop dead from a stress induced heart attack, all the other stuff is pointless.