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 rotating it like this acts like a buffer,rather than something that is only accessed in dire emergencies and would be out of date or less effective due to age.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

Governments used to maintain grain stockpiles in case of famine. A modern equivalent could be run for vastly less than current farm subsidies. Especially if stocks where rotated and mostly refilled in years of massive surplus.

PS: At the extreme end Honey can be stored for thousands of years at room temperature.