First, if you look at who had the tiebreakers, and place them accordingly, these are Bo's actual division standings in the Big XII North, then B1G Legends, then B1G West:
2nd
1st
1st
3rd
1st
3rd
3rd
So like I said, no closer to winning a championship in year seven than you were in year one, while coaching at a blue blood will never be sustainable. 7 years was more than enough time and data to conclude that Bo's ceiling and floor were an inch apart, and trending downwards rather than upwards.
Second, Bo's particular style of 9-10 wins would not put NU in the playoff hunt (read, top 12-14) every year. If you don't believe me, here's where we ranked after conference championship weekend every year and how many wins we had at the time:
2009 - 10 wins, ranked #20 (not in the playoff hunt)
2010 - 10 wins, ranked #18 (more or less not in the playoff hunt but maybe in the most chaotic scenario)
2011 - 9 wins, ranked #21 (not in the playoff hunt)
2012 - 10 wins, ranked #23 (not in the playoff hunt)
2013 - 9 wins, unranked
2014 - 9 wins, unranked
Last, there's absolutely zero scenario where Bo continuing on as he had been would stay at 9-10 wins a year. He got remarkably lucky to coincide with the worst in decades versions of OSU/Mich/PSU, and was also coaching in the B1G before the middle and lower tier teams suddenly had hundreds of millions to drop on high caliber coaching staffs and state of the art facilities etc.