Agreed we're in the successful group, easily. Sucks that NK exists as it is, but they are isolated and have no way to expand or threaten the world system. The fact that we can have websites like this, and people actually can sit in the basement and work on the math means we are doing well, up to this point at least.

My guess is more of the failed earths were long ago. Like humans continue to wander around in small tribes for millions of years and never get beyond stone-age technology. We are eventually wiped out by a meteor or some such.