What lesson in Civil Defense planning is brought home by Dan's comments on stockpiles?

In chapter 7 Dan says,

“The place we should have built up stockpiles was out in the country, like Timucuan County. Stockpiles weren’t going to be of much use in the cities because after "The Day" there weren’t going to be any cities left. But where were the stockpiles? In the cities, of course. It was easier.”

Dan's point is that although stockpiles in cities are cheaper to keep and administrate, they are the first to be destroyed or stolen in an emergency.