This is really not the case. You buy food from farmers, who can keep money, and you use existing government capacity to distribute it. It's been done before and can be done still.
Spend some time volunteering with local emergency preparedness teams and you'll get a better sense of just how much of the US food system is essential "just in time"
The more urban a place the more "just in time" everything is because the space is more valuable doing literally anything other than warehousing calories
