The reason why I have him coaching for two more seasons in this hypothetical is that it would bring him to seven full seasons at ND. This would be the same length as Elmer Layden, who was the longest tenured ND football coach who did not win a National Championship. Moreover, only four men ever coached the ND football team for 8 or more seasons. Three of them (Rockne, Leahy, and Ara) won multiple championships, and the fourth (Holtz) arguably deserved a second championship in 1993.
Anyway, let's suppose that at the end of the 2016 season, Kelly does not leave voluntarily (NFL, another college, retirement, etc.). The only choices are to retain him or fire him.
If he had not won a championship by 2016, would you fire him?
If you would consider retaining him beyond the 2016 season, despite not winning a national championship, what would he have to accomplish during the next two seasons in order to keep him (i.e. two playoff appearances, one playoff and one access bowl appearance, etc.)?