This is the only part of your post I disagree with. I don't think we can count on Shafer staying here long term if he is successful.
If Harbaugh leaves Michigan again for the NFL and Shafer has the level of success people here predict, he would leave for that job in a heartbeat (especially with his kids being in college in that time)
This is why I think you get the best coach you can. If he leaves after a year for a better job, that typically means it was a strong year for the program and the view of that program is higher in the eyes of other coaches.
I look at a program like Arkansas State:
http://www.sports-reference.com/cfb/schools/arkansas-state/
Freeze goes 10-3, leaves next year for Ole Miss
Malzahn gets hired, goes 9-3, leaves next year for Auburn
Harsin gets hired, goes 7-5
There will never be another Boeheim in college sports. Money talks.