For a franchise that had already given the N.F.L. an owner who implored his players to show the world they were “not a bunch of horses’ asses,” a man so desperate to get away he resigned as “HC of the NYJ” moments before he was about to be introduced as the head coach, and, a mere three weeks ago, an entirely new category of ineptitude — the butt-fumble — it might be difficult to recognize rock bottom.