I think your expectations are overly optimistic. Perhaps it wouldn't be 99.9999%, but in the event of global nuclear war, supply chains for virtually everything (including food) will come to a complete halt. People in cities will be utterly screwed when fuel and food run out.
People in farmland might not be that much better off. Masses of starving, potentially-armed people searching for food will not necessarily be the most respectful of people's property rights. We can expect animal wildlife populations to plummet as they're killed for food, and agricultural output to drop precipitously as supply chains for fuel, fertilizer, and non-terminator-gene seeds go to zero, not to mention as it becomes exceedingly difficult to protect large patches of farmland from raids.
People in farmland might not be that much better off. Masses of starving, potentially-armed people searching for food will not necessarily be the most respectful of people's property rights. We can expect animal wildlife populations to plummet as they're killed for food, and agricultural output to drop precipitously as supply chains for fuel, fertilizer, and non-terminator-gene seeds go to zero, not to mention as it becomes exceedingly difficult to protect large patches of farmland from raids.