Yes, I am familiar with just in time delivery. Say the grocery stores have enough to feed the population for three days.

So, 1 can meal / person / day x 3days = 3 can meals/person Now we have 5,000,000 people. That is 15,000,000 can meals.

For simplicity let's just call 3meals/ day 365 days / person = 1,000 meals / person x 1,000 people that is only 1 Million, so still lots and lots of cans for a few years.

I agree that our society functions on continuos resupply, but people do not easily comprehend how much a million really is.