Yeah, I kind of take it for granted that humans can survive on what exists around them ... essentially everybody I know in rural W.Australia can do so. Most farms here keep a back log of every bit of kit they ever had, going back to the 1880s and earlier in some cases - I've helped strip down and rebuild a couple of Allis-Chalmers tractors in the past four years and the local small town car museum has a crazy number of historic vehicles (three wheels, steam powered, one time speed record holding, etc) that are kept in working order by locals.

I've renovated old old houses in Fremantle and flipped them with very few contractors (while working on bleeding edge code bases) and built air strips in the PNG highlands, worked with wood workers, glass blowers and metal workers, etc.

I suspect some people have spent a little too long behind screens and forgotten how to shear a sheep, draw, card, spin, and knit a jumper.