[88913527]

Even then, supermarkets being stocked isn't a self-sustaining vacuum. Not all goods sold are produced within 100 miles. The fields are cleared with industrial equipment, sourced with semiconductors and parts produced across continents, the grain is processed in a facility, the product is delivered by a driver, and some point later a 99¢ box of pasta is on the shelf. Very few items can carry on forever due to complete sourcing, production and distribution occurring as closed systems. We simply don't have that level of vertical integration.

[KozmoNau7]

Equipment keeps on running until it needs to be repaired or replaced. If you can't get parts or new machinery at that point, you're screwed for a while, currently that can be a long while. Those situations will add up and get worse and worse.