The difference between him and good singers is that he has this pureness and innocence in him. Simon sees it. He even said it on Ellen Degeneres' talkshow. Quoted, "William is adorable." He sees the goodness in him.
I know a lot of talented singers are SO FULL OF THEMSELVES it almost pisses me off, but that's the way they are.
Reply if you disagree with me that a lot of talented singers are full of themselves..aka: the rejects that are talented off of Idol . Quoted, "OMG, They just eliminated /THE BEST/ singer in this G**DAMN competition!!!" etc etc etc.
Edit: Yes he did get rich, some of the girls from school bought his CD. Although I think he's got the heart of a true fame-winner, I wouldn't bother to buy a CD--I'm not that into him. Haha.