Me and DH have made sure we have quite a bit of food in the house for about the last 30 years.
I always find it strange that so many people have so little food. Even if you don't have much money you can gradually build up a stock by buying an extra tin or extra bag of rice, pasta etc.
Also people say they have no room to store extra but most people do have room somewhere. Under beds, on top of cupboards, wardrobes, in the loft, in a garage or shed.
Apart from shops running out of items, there are quite a few reasons someone may not be able to get to shops. They could get snowed in and then, obviously, no delivery van could get to them, roads could be flooded, you could be too ill to go out, you could be without a car for a while.
We got snowed in many many years ago. We had only been married a couple of years, living in Kent but not that rural. We couldn't go anywhere for over a week.
After that we have always had at least a month's worth of food - things like rice, pasta, chickpeas, different lentils, different beans, flour, tinned tomatoes etc. Also lots in our freezer - bread, milk, veg, home made soups, home made meals.
At present we have food for at least 2 months of different meals but even after that we could live on lentils, chickpeas etc for probably another month or more.
The only people that know we have so much food is my family. They don't get it as they go shopping every week which I just find strange. I don't like shopping enough to go that often and why would you need to buy food that often