Yes he is responsible for everything as the HC, offense, defense, and special teams. First 3 years he was here the defense was good, the offense and special teams very poor. so his grade for the first 3 years is what 33%? 4th year all sides of the ball failed, but we look past that because of injuries ok, this is his first year in which he has 2/3's of his team playing well, and the side he is most responsible for(not because he is an offensive coach, but because he chose to keep himself as OC so he is head of the offense and is therefore directly responsible for how that unit performs) It doesn't matter that BoB played defense in college, he has coached for 25 years, and only 1 of those 25 was spent coaching defense and that was back in 94. He never truly learned how to coach a defense at the college much less professional level. Also I do not believe teams offense and defense operate in side a bubble, but your sweeping generalizations and lumping everyone who disagrees with you together shows about as much of a lack of acumen as your petty insults earlier did. Btw BoB has said RAC is a huge asset to him because he can hand the defense over to him and not worry about it. So what should we make of that?
Next point, yea losing the locker room is a general sign of a coach needing to be shown the door, but it's not the only one. There have been a multitude of player coaches, whose guys would run through a wall for them, who never lost their locker room but couldn't hack it as a HC, probably because like BoB they lack the proper managerial skills to do the job.
Do you not think this team needs an OC? if so why? trust me ALL of us remember BoB's little protege Godsey, the guy he personally groomed from the time he was BoB's college QB, and brought him to every coaching stop along the way. Yes we all remember how much of an utter failure that guy was at being our OC. But why should that give us any faith in bob to identify and coach up talent both with players and his coaches? He made Godsey the OC, he taught Godsey how to play call, Godsey's failure is BoB's failure, but I guess you will ignore that part huh?
I will say this again all success falls on your coach, just like all failures fall on your coach. O'Brien has failed in more ways than he has succeeded, not just player personnel wise, or play calling wise.