It gets worse. There is a phenomenon among Chinese expats known as Daigou[0]. It is a common problem in Australia[1], for example. Groups of expats will swarm a store, circumventing per person limits, buy out an entire shelf of a "luxury" good (videos of baby formula for example are on YouTube), load up their trucks, then drive over to the next town.
They've likely been doing the same in the US. Masks have been totally sold out since January (when I started looking for them) while the vast majority of Americans were still totally unaware of the virus.
0. https://en.m.wikipedia.org/wiki/Daigou
1. https://m.youtube.com/watch?v=tSjeDH22njk