Sure, but are any of these "don't worry guys I torrented a database dump, it's safe now" folks going to go to the trouble of actually doing that? They're not even downloading a full backup, just the current version.

You need to devote a lot of bandwidth to keeping continuously up to date with Wikipedia. There's only a few archives out there that are likely doing that, and of course Wikimedia Foundation and its international chapters themselves. Those are the ones who will provide the data needed to restart Wikipedia, if it actually comes to that.