No, what you're missing here is the ability to self analyse sufficently. I'm sure Wenger does. Most humans doing their job do that. Its stupid to think otherwise.
But how effective that analysis becomes is the key part. Fergie I'm sure asked himself enough difficult questions to remain on top. Wenger probably doesn't go far enough or doesn't rely enough on people around him enough to face some home truths. Whereas Ferige probably did do that.