You cannot simplify the situation by determining who is calling the plays. There is a lot more involved in just calling the plays.
There is preparation, development of the quarterback, the mental aspect of the athletes, whether all the athletes are unified to perform for the head coach, etc.
If 100% of the players are loyal to O'Brien and zero are loyal to Gailey, then BOB is the problem and should have to go. The players should be 100% behind Gailey and BOB should be secondary. If not, the players are at fault and BOB is at fault.
In other words, I don't really give a flip what anyone is hearing from the players, if they have not committed 100% to Gailey and a unified football team, the players are at fault.
If one coach has to go, it should definitely be O'Brien. If Gailey has to go, then O'Brien should also have to go. It cannot be any other way if the team is to have success in the future.
If Gailey were to resign, and O'Brien stayed at Tech, I would be the most shocked person around. I would then know the administration has no idea how to run a program. I just can't believe a sane committee could make that kind of decision. I don't believe it could happen.