Are there examples of coaches in the Big Ten in the last 15 years who did not turn it around in five years but did so when given more time?
This a million times. The OP states that there have only been two coaches in the last 15 years that have turned programs around. I'm not sure why Brady Hoke is excluded from that list, other than Michigan doesn't count, but if Michigan, Ohio State, Penn State, Wisconsin, Iowa, and Nebraska are all automatically disqualified, we're really only talking about 6 coaching spots over 15 years, which is a pretty damn small sample.
But let's go down that list, shall we?
Illinois
Ron Zook (2005-2011)
-First five years in B1G (12-28)
-Two years after that (6-10)
Ron Turner (1997-2004)
-First five years (15-25)
-Three years after (5-19)
Indiana
Bill Lynch (2007-2010)
-First four years (6-26)
Gerry Dinardo (2002-2004)
-First three seasons (3-21)
Cam Cameron (1997-2001)
-First five seasons (12-28)
Michigan State
John L. Smith (2003-2006)
-First four seasons (12-20)
Bobby Williams (2000-2002)
-First three seasons (6-15)
Purdue
Danny Hope (2009-2012)
-First four seasons (13-19)
Now, which of those coaches above deserved more time? Any of them? Did Illinois really benefit by two more years of Ron Zook or three more years of Ron Turner?
Four years is enough. If progress hasn't been made by that point, it never will be.