It's not just Covid. Look at the medical world. Generic products compete on price and there is little profit margin--not enough to warrant overprovisioning against problems. And meeting FDA requirements for new activities means new players can't just jump in the game. (And we sometimes see this done maliciously--control all active production of something and shove the price through the roof.) One factory has a problem and there can be huge problems downstream as a result.

The only solution I see is for the FDA to include supply reliability in it's determination of whether a system is acceptable.