[moonchrome]

There's a lot of practical/contextual knowledge that isn't documented, and what's documented isn't guaranteed to be correct or can be misleading (terminology changes, standards change, some things are implied because they are obvious at the time, etc.)

[bluGill]

Though knowledge of experience is sometimes wrong as well. Sure it works - unlike print where mistakes (sometimes intentional to hide a secret) can tell you something that cannot work, but that doesn't mean it is a good way to do things.

[1970-01-01]

Give some examples? That kind of 'undocumented' knowledge is lost because better tech has completely replaced it. I'm talking about inventions like the Spinning Mule or the steam engine. We have superseded them with electric motors and logic boards.

[moonchrome]

First thing that comes to mind is friends father was hitting retirement age after working at a petrochemical/plastics facility for ~20 years, was in charge of maintenance of some section. I think he told me the owner had to call him twice to help diagnose problems that were causing product outages.

These things don't get built on a whim - there's risks, regulations, documentation, procedures, experts, etc. At the end of the day you have people doing the work for decades, with an intuition about how things work.

Given infinite time you can recreate anything - but by the time you're done putting the puzzle together you're out of business.

[FooBarBizBazz]

One example is how they had to reinvent the material codenamed fogbank.