Ummm....
Wait.... I'm the one who's smug?
Gotcha.
You seem to ignore the fact that dustole never has played their characters in a way that allows for lasting power. His goals involve creating more conflict to keep islands interesting. I would label him a destabilizing force.
I doubt that dustole ever expected for the realm led by him to last forever, but he splintered Arcaea and left it unstable, which I think was the point.