Let's play what ifs.
Would Tampa Bay have made it to the SB without Gruden?
Nah. Even without pointy headed Tony Dungy leading the way, the Bucs NEEDED Gruden for that achievement.
If Jon Gruden remained head coach of the Raiders (and obtained personnel authority), would they have slipped to the debacle they are today?
Not a chance.
Will Jim Harbaugh leave his peachy position as head coach of the Stanford Cardinal to become the next head coach of the Raiders?
Doubtful BUT, he is the likely leading candidate on the burner right now.
If for some reason Jim Harbaugh decides to leap into the fire, will he have a chance at being successful?
He'll have to work his tail off as Gruden did, but chances are slim for success without personnel authority.
It's just not possible to be a hard charging, innovative head coach for Al Davis because the Raiders are all about Al's ego. He does not stand for independent thinking. As much as people may deny it, you have to follow a script. If Al does not have the glory of the seeing his decisions pan out then it's not ok for the head coach or a GM to take any credit. That's what this is all about, a little boy and his sandbox.
Gruden had to painstakingly prove through film cuttings why Al's ideas would not work and then defy his master more than a few times to get his point across, ultimately leading to his trade to the Bucs.
All of Al's hires have to be submissive to his authority not just in word, deed, and action but in conscious belief system.
Gruden managed to do this because he needed to at the time. As a young head coach, he had to establish his path in the NFL. He did this successfully as best as possible.
Jim Harbaugh is similar in this regard and therefore stands a chance at following the same blueprint but it's a long-shot he will rise to the occasion. The Raiders were not in as worse shape as they were when Gruden took over. Harbaugh would have to be superman to turn the ship around.
Bottom line is any coach would have to be the very best there is to work with Al's ego and return the Raiders to a semblance of a competitive team.