2) As long as we assume that society continues on its current trajectory forever, then yes, there's nothing to worry about. But if it's true that we're in the twilight years of US dominance or relevance as a world power, then we could be in for a significant period of upcoming political/economic turmoil.

So here's another way to look at it: How would the monks and agrarian fiefdoms of the middle ages been at handling a monster leftover by the Romans?