British Archaeology

I know. When a technology is replaced by something better, we tend to lose common knowledge, and sometimes all knowledge, of how to do it most effectively.

Sometimes, it's not replaced, just lost and we can't replicate it (Roman concrete, until recently). Sometimes, it's just not relevant and the majority of people never learn or know how to do it anymore (knapping). Sometimes it's lost because nobody has done it on so long and there are few or no records - we can reverse engineer and make educated guesses, but we can't be certain about how they did it, and we probably can't do it as well without cheating with newer technology (Egyptian pyramids).

I completely agree with you, and knapping is one of my favorite examples. It's something nearly everyone could do, and do pretty darned well, at one point. And now now almost nobody can do it, or even know how to, except for some indigenous communities and a few enthusiasts. Giant public works projects, like Stonehenge, Pyramids, and Easter Island are even harder, because they did it all the time and were good at it, we have so little written record of how because nobody bothered to write a manual, and it required the combined effort of a community.