Supposedly, CBS moved their own promo ads out of the first half to attract those advertisers who could be still be debating getting in on the action. Rumors say that as of Thursday morning, there were at least two :30 spots left for this Sunday's Super Bowl game.
The price has been brought down to $1.9 million per spot from $2.3 million. As CNN/Money mentioned in an article two weeks ago, Apple wasn't going to advertise, but did inquire how many spots were left.
Maybe, just maybe, they were waiting for this.