I can't think of the name of the theory, but the general idea is that it would be very difficult to rebuild to our current level of technology after a cataclysm

I can't think of the name of the theory, but the general idea is that it would be very difficult to rebuild to our current level of technology after a cataclysm event because all of the easily reached surface resources required to bootstrap it have been picked clean. Even the near-surface resources are gone, requiring us to use massive open-pit mines or deep mining/drilling. Some material could be recycled from crumbling cities I imagine, but even recycling most modern materials requires a certain minimal level of technology, no?