I saw picture on one of the liveblogs (sorry, can't remember which) before the presentation started that showed Scott Forstall standing in a group with Phil Schiller, Eddie Cue, and a couple other people. So he was there, but as has been said, I think he's usually on stage to talk about iOS itself, and other than the very minor 5.1 update, there wasn't anything to say on that front yesterday. I'm sure we'll see him when iOS 6 is announced.