Being "The Guy Replacing 'The Guy'"

I took a look at the list of winningest FBS coaches and compared the top 5 who spent the majority of their time at one school and how their successors did. My criteria was, the coach in question must have ended his career in 2000 or later.

Here is a blind resume of the guys who followed.

Coach 1: 2 seasons, 62.5% winning percentage
Coach 2: 4 seasons, 56.63%
Coach 3: 1 season, 46.15%
Coach 4: 5 seasons, 61.67%
Coach 5: 8 seasons, 78.3%

Coach 1 is current NFL head coach Bill O'Brien who took over at Penn State for reasons we will not discuss here.
Coach 2 is current Pine View (UT) High School coach Gary Croyton who took over after Lavell Edwards left BYU.
Coach 3 is current Cincinnati head coach Luke Fickell, who took over at Ohio State following Jim Tressle's issues, and was replaced by Urban Meyer.
Coach 4 is Fu
Coach 5 is Jimbo Fisher, who was head coach in waiting for several years before Bobby Bowden was ridden out of town.