It’s unsettling to think that humanity has lost knowledge it once had, but it happens all the time. Anyone here know how to harness a horse to a buggy?
It's not certain that much knowledge has been lost, although much of it is in "endangered" status of preservation. There's a kind of silk netting made from the hairlike tufts of a certain species of clams, only practiced by two people IIRC.
Some lost knowledge is being rediscovered. A well-known example is making Damascus steel; it's now so ordinary you can order it online.
And, yes, I feel confident that with a few weeks, a rope, and a really good reason - almost any American could strap a horse to a buggy. It's not rocket science and countless humans have done it before.