Exactly this. Consider the "hand axe" -- a multipurpose stone tool made contiguously by basically almost all bipedal hominids (if not more) for a million and a

Exactly this. Consider the "hand axe" -- a multipurpose stone tool made contiguously by basically almost all bipedal hominids (if not more) for a million and a half (or more!) years. Homo erectus, neanderthals, sapiens, etc. Then abruptly lost around the Paleolithic to Neolithic transition really. Apart from a few anthropologists who've studied to try to recreate the technique. It essentially "defined" what it is to be human for over a million years, and we can't do it anymore. I'm not saying it's a useful skill, only that this is a piece of cultural memory lost and that's kind of sad. It's not like hand-etching circuit boards, which is nothing more than a transitory technique to accomplish a goal until we found a new way. Stone tool making (and language) is what distinguished us from every other species on the planet, and was one of the central activities that people did with their time for hours on end, and is probably one of the key things that got us to "sharpen" our problem-solving brains and develop the other skills we rely on now.