The Internet is "failure-resistant" in the senses that (1) individual networks going down don't take down the entire Internet, and (2) networks that peer with other networks can still be routed to so long as at least one route is still online.

North Korea's failure demonstrates both of these properties: the Internet is still online, and the routing failure has manifested because all of their peering routes are down.

The ability to route around failures is predicated on having a sufficiently high degree of interconnectedness. Even your home network won't magic up a new connection if someone decides to cut your cable line. NK's network is poorly connected to the rest of the Internet, and so there is limited ability to "route around failure".

North Korea is poorly connected to the rest of the internet, by their own design. I know that a few years ago, there was only one link to the outside; not sure if that's changed, but I have no reason to think that it would have.

If you are the failure, no, it does not.

[EDIT] I immediately saw that that could be read as a swipe at NK, which wasn't how it was intended. Just that if you're on the wrong side of a failure, you're not gonna be able to "route around the failure".

It routes around failures, the timelines for delivery are not promised though.

I’m not so sure this applies with centralized tracking/filtering.

Has it ever actually done that?