Steve Jobs wasn't IT guy, but he was insane marketing guru. He could sell you box full of shit and make you think it's cake.
He was able to sell mid-range products as high-end.
Steve Jobs (I really don't like him but must respect him) did snowball the fast train.
Cook is pretty useless, but he's got the "wheel" of really fast train and it will take a lots of time for the train to slowdown.
RE: Apple Marketcap: $1 Trillion Line Crossed