I will always believe that Punk was LEGIT quitting after his "Pipebomb" promo, Vince looked at the ratings and publicity it got, and as a stipulation of him not leaving and taking his heat with him Vince let him keep the belt for a year+.
This would also be the reason that Cena was ALWAYS booked like The Champ even though he never had the belt.... Vince was screwing Punk for bullying him out of the belt and contract by underbooking him but not burying him.
Making this the longest and most heatless title reign in history.