that's why stockpiles should be kept by government. they don't need to make money on it. should be easy enough, have 6 months worth in a warehouse, ship the oldest out the front of the warehouse to the supply chain while topping up with new product at the back. rotating it like this acts like a buffer,rather than something that is only accessed in dire emergencies and would be out of date or less effective due to age. the relatively small costs of a warehouse would be negligible