https://www.youtube.com/watch?v=pW-SOdj4Kkk
His point is basically that there have been times in history where the people who were the creative force behind our technology die off without transferring that knowledge to someone else, and we're left running on inertia for a while before things really start to regress, and there are signs that we may be going through that kind of moment right now.
I can't verify these claims, but it's an interesting thing to think about.