I thought the same, until I looked back at when experiential knowledge was lost and then reacquired. If it is within a generation or two of loss and recovery, t

I thought the same, until I looked back at when experiential knowledge was lost and then reacquired. If it is within a generation or two of loss and recovery, the process seems to proceed along the lines of what you mention. Beyond that, and recovery success rates looks like a cliff function. Metallurgy has been independently worked upon around the world, and specific aspects lost many times over. Someone demonstrated they were on the right path to working out precision hand-built gearing with the Antikythera mechanism. The discovered mechanism wasn't very accurate, but we lost that tech for about 13 centuries. Another way of considering that lost tech: it took about three centuries to get the first mechanical computers from the 14th century onwards (about when we recovered the level of the Antikythera mechanism's tech); we could potentially have had software on mechanical if not electronic computers say, 7 centuries ago, if the Antikythera tech was not lost. Fast, bi-directional mass communications seems to be key to discoverability. Lose that, and all sorts of losses apparently accumulate quickly. Of more immediate concern to me is the economic effects of classifying certain economic verticals as "low margin" and then deprecating them, as if some kind of central planning committee decreed that the industry shall forevermore never cross-pollinate or value-add any other industries. I'm not convinced it is that straightforward nor predictable. Somewhere in China at this moment, some college kid studying materials science has parents who work at a "low margin" garment factory, who through osmosis over the decades taught her about the ins and outs of industrial-scale, high-precision thread-manufacturing and tight weaving, and she's noodling about adapting that tech to manufacture say, glass foam insulation at 1/1000th the current cost, and revolutionize the global insulation industry forever. It certainly is economically efficient in our local maxima to arrange our "developed-world's" industrial policy in this manner, but I think the jury is still out on whether or not it is sustainable; final arbitration will be history in a hundred years, but my bet is on China, who seems to have no qualms absorbing the industries "developed nations" no longer want, and doesn't seem as eager to divest as much or as fast to "lower tier" economies. > ...and we could do it again assuming a large relatively stable global economy. Here is where I have concerns "there be dragons". I've yet to read of many losses of industries (much less civilizational collapse) where there was sufficient stability to quickly recover; usually the recovery process, even when successful, was arduous and time-consuming. As rapidly as the global economy changes now, and with the global economy's new normal turbulence, I'm not convinced that recovery is any easier today than in earlier eras. I am thankful for people who publish information like "From NAND to Tetris".