Comment by mschuster91

> The knowledge is still there

Tell that to the people who lost FOGBANK, or rather, the knowledge and most importantly the practical experience on how to make it. Or Emmentaler cheese - the one with the bubbles. Turns out, you need something only discovered when someone noticed the bubbles began to vanish... small contaminations from microscopic hay particles [1] that went away when manufacturing switched to fully sealed vats.

There is always, always undocumented steps and unknown implicit assumptions involved in any manufacturing process. No matter how good the documentation is, you need the practical experience.

And that, in turn, is also why the US is producing so much military surplus - should there ever be a full blown war with Russia or China, or there be any other need for a massive invasion land war for whatever cause, there is a shit ton of stuff on stockpile and the production can be rapidly scaled up by experienced personnel training fresh recruits. That would be outright impossible to do if there were no experienced personnel.

[1] https://www.yahoo.com/lifestyle/mystery-of-disappearing-hole...