I really think that Fisher is his own biggest problem. His problem is that he is not self critical and has failed to adapt to the changes in the game. It is not like the offenses evolved over night. The entire NFL has geared the league to become a passing league. You need a great offensive system with you need really smart players to play in that system. Fisher wanted to play an offense that worked in the 80s and 90s and that just won't cut it.
Fisher loved the freak athlete over one with brains, he killed QBs and refused to get an offensive coordinator that would a modern day offense. If he really wanted to get back into coaching he would start conceding these points and making a plan to fix them that would interest teams. I doubt anyone calls him but if he really wanted to I bet he could convince a team or two that he has a plan and would be better than any of the young turks out there.
Sadly I think the issues that caused Fisher to fail are still there and that he has stopped learning and growing. Sounds like he is having fun hunting so maybe he should just enjoy himself and give up his dream.
