I have a notion that AW's whole advancement system, ungiven future especially is about drawing a game *towards* a close.
As in, as you're playing the game, you eventually end up with characters that can deal with any problem the setting throws at them - seeing beyond the maelstorm, making allies, etcetera. At some point, you're inevitably going to say - if anyone's going to fix Insurmountable Problem, it's going to be Player Character! And then you play to see if he does, and whichever way that falls, the game is done.
Or you could go on forever with a new character + retire to safety / change playbooks, but those mean you're not playing the same game anymore - you bring new characters with new interests that change the 'end game' conditions.
So, uh. Advancement-based story-pacing? That doesn't sound like it's a new thing, but it's there.