Reusable containers are used at almost ever restaurant in the world that serves on plates.
Reusable containers are currently not cheaper and so they're not used - but the fact that they're not used for non-food items is pretty indicative that it's a cost thing, not a safety thing.
Do you really think what you've posted make sense? Or do they not teach you basic food safety in schools, like finish your food ASAP after removing from heat, heat any cooked food to 84C for 1 minute for sterilization, immediately refrigerate dishes not intended for immediate serving, etc until it gets annoying having to fill in same quizzes every few years?
It really feels strange that this level of basic understanding hasn't permeated across, at least, developed nations. The humanity collectively got as much as 6x mortality variance _among developed countries_ with COVID. It's appalling if things like this had been a contributory factor.
Reusable containers are currently not cheaper and so they're not used - but the fact that they're not used for non-food items is pretty indicative that it's a cost thing, not a safety thing.