Interestingly it seems that Norman was a rich guy who REALLY wanted to do blue collar crime. Like he'd have more power and influence in his civilian position, but even going back to his original goal of becoming a mob boss, he just wanted to get in that action.
I kind of think that him having amnesia when he wasn't dressing up was mistaken for a split personality in adaptations like Spider-Man the animated series and the perception of Raimi's Norman. I'll have to look at older issues again, but did amnesiac Norman really feel like a completely different person?