This posits a simplistic economy where everyone can predict the future. The real world has risk and unknown effects. If someone stockpiles a lot of masks on t

This posits a simplistic economy where everyone can predict the future. The real world has risk and unknown effects. If someone stockpiles a lot of masks on the chance that they'll be needed, hoping to thereby profit, they're taking significant risk, and reward for that is not unreasonable. This is essentially how finance, banking, markets, and pretty much our whole economy work. The idea that producers should only be able to charge a modest margin over their "costs" is pernicious nonsense. Furthermore, if you punish this sort of risk-taking intensely enough, producers will just shut down during unusual times (the exact opposite of what is needed).