[ethbr0]

The analogies are apples and oranges, as all of them face existent incumbents with massive resources.

Which is where the point about population comes into play. Refining low-density elements (e.g. rare earth) into purified form is most of the difficulty and industrial base.

The available recyclable material from a civilization with a couple+ orders of magnitude larger population would be more than sufficient, even if chemical reprocessing is required.

Consequently, you run into an either/or. Either (1) there wasn't substantial loss of life (and industrial base), in which case no need to reboot, or (2) there was substantial loss of life, in which case there are more than sufficient recyclables.

And it's also hard to imagine a scenario by which we lack essential inputs. We've got more than enough crude oil or rare earths for the future. The only arguable example I can think of is helium...