>then you have to rediscover how to do it the old ways.
Depends on how many of the old ways are faithfully recorded in more permanent records. Language, and by follow up, reading are the most important technologies ever. As long as I have your language and instructions in writing almost anything can be accomplished.
In theory, but in practice there are some kinds of knowledge that are hard to develop without a mentor. And there's lots of little things that are so obvious that its not worth writing down, but then years, decades, centuries later those things are no longer obvious.
All of that translating written material from one culture to your own and then implementing it is by no means a trivial task and shouldn't be taken for granted
Depends on how many of the old ways are faithfully recorded in more permanent records. Language, and by follow up, reading are the most important technologies ever. As long as I have your language and instructions in writing almost anything can be accomplished.