It's the best way to book him. He's gotten over on the fact that he can win. Granted, he was a cheap bastard about many of them, but they were pretty much all him. Giving him backup now would take away from that momentum he's built up.
A recent house show commercial I saw during RAW talked about seeing CM Punk, Sheamus, Daniel Bryan and many more. Maybe because it was advertised for the tri-state area which is big on in-ring product, or maybe he is just that important to the company.
Right now, he's their top heel. Sadly, followed by Kane, Alberto Del Rio and Dolph Ziggler.