Again, folks, go back and read the question. It was a what-if, a thought experiment, not a supposition of things to come.
First (and i reiterate) I did not say food or ammo. I said food AND ammo. Food for short term, ammo to get food for long term.
Mak... yes, gold "became a medium of exchange in every society I've ever examined...", but only after the society established a standard of living that allowed for some level of vanity and the luxury of using non-essential goods as a means of exchange. Again, kinda hard to eat gold, and kinda hard to use it to buy anything when all everyone else needs to do is eat, too. In those cases, food, clothing, and shelter, or the means to acquire such, become the most valuable. Only once those basic needs are met can the society afford to place a value on non-essential items.
Oh, sure, people will try as it is human nature to to hoard things we think have value, especially in times of crises. Unfortunately, reality will only allow a certain order to things, beginning with basic survival (i.e. food, clothing, shelter, and a way to get them). Once that is satisfied the society can begin placing an inferred value on non-essential items as a means of barter.
Jamis... IIRC scientist have been able to successfuly germinate several-thousand-year-old seeds found in Egyptian tombs. Vacuum sealed and kept in a cool place, I daresay most seed would be viable darn near indefinitely.
Brad