Why would he?
Some Raiders fans have noticed how diplomatic Jon Gruden is in everything he says or does concerning the Oakland Raiders, and this provides some measure of hope he would consider returning as head coach.
Well, that’s not going to happen so long as Al Davis is alive. Al is first of all threatened by Gruden’s popularity. In Al’s world, no one is allowed to take any credit for the team’s (potential) success more than he is. Al is a very smart guy but he’s also completely absorbed in his own megalomania.
This is why the team is so bad right now.
He follows his own patterns for failure in a mistaken belief he can fix everything by himself. To him, so long as he controls any possible turnaround (and therefore, controls the glory along with it), he is willing to begrudgingly absorb the failures each passing season.
Gruden would not take a job where he did not have final say on the roster, which was a sticking point in his being re-signed to a contract extension when he was head coach for Al. This led to his famous trade to the Bucs.
Every season, NFL head coaching jobs open up, and Gruden has to be considered a strong candidate for any of them. He has no reason to want to deal with Al again and he won’t. Despite what anyone says or thinks they know, only a true fool would walk into a situation set up for failure.
Gruden was able to succeed as Raiders' head coach because he worked extra hard to comply with Al's oversight. At this stage in his career, he doesn’t need to do that to be successful elsewhere. He can apply those extra energies to other things.
No coach would want to deal with Al’s constraints unless they were not candidates for other head coaching jobs or they had a personal as well as contractual agreement with Al that clearly specified the boundaries of control the coach has.
Gruden was not able to get that the first time around but he worked within acceptable boundaries until it came time for a contract renewal. At which time, Al balked and let him go to Tampa Bay.
That pretty much sums up the reasons why Chucky will not be back to rescue the floundering rotting hulk, knows as the Oakland Raiders franchise.