Not to mention, I seriously doubt NFL owners are all that excited about his SB win from six years ago. It's more of a "what have you done for me lately?" type of league.
Pete Carrol, Bill Belicheat, Jeff Fisher, John Fox, Jim Caldwell, Andy Reid, Tom Coughlin, Lovie Smith and Ken Whisenhunt are all currently on their second NFL head coaching jobs without having won even ONE Super Bowl in their previous incarnations.
At the end of every NFL season there is generally a clamor for Bill Cowher to return to coaching after having only won one Super Bowl. Hell, even Gruden's name gets tossed in the hat and it's been ages since he won.