I've wondered if Sullivan set up the bomb on Sculley, basically daring him to fire Jean-Louis. Sculley is a lose cannon that fires anyone that gives him needed feedback. Jean-Louis is important enough that firing him will bring that into sharp relief.

Sculley fires Jean-Louis, the resulting blowback doesn't convince Sculley of anything and Sculley is too dumb to know he needs to leave. So two years later the board is forced to can him.