I'm saying Marcone the name has all kinds of connections to who he is, even the very inflection of it can change who he is, that's why he always gets erkked at Harry when he calls him john, he's hitting that tiny tuning fork.
The choice to change your name is to try and change your identity associations. If he switched back to his original name he'd effectively be giving up the notion of crime lord Jonny Marcone, his sense of self. He would in effect be a whole different person. A person he gave up on being once before.
*its an effective theory to utilize.
**sweet ambrosia, COFFEE!