Every major CF power has had down periods and their fans went through the same conflict---no one wants to be the next Notre Dame, wandering in the wilderness not giving the new coach enough time and changing coaches every few years. All of these teams turned it around and were back to their winning ways.
Started me thinking about how fast the turnaround took. I looked at only the top teams for all-time for wins who in modern times had a major downturn and brought in a new coach: NU, UT, OK, 'Bama, ND, USC; and a few newer ones like FL, FSU, GA.
One common thread--they all won right away (at worst had a middling 1st year except Sabin) , and won at a high level every year thereafter. I recognize that every program is different and there's a lot of parity these days. I just couldn't find any examples of big-time programs that needed several years for the new coach to turn things around. But coaches like RR and Brian Kelly do have a strong track record of success as CFB head coaches---maybe they'll start a new trend.
Here's the programs, with coach's first year and all-time record at that school:
OKLAHOMA Bob Stoops 7-5, 127-31
NEBRASKA Bo PelinI 9-4, 30-10 and Bob Devaney 9-2, 101-20
TEXAS Mack Brown 9-3, 132-34
ALABAMA Nick Sabin 2-6, 37-11
FLORIDA Urban Mayer 9-3, 64-15
NOTRE DAME Lou Holtz 5-6, 100-30
GEORGIA Vince Dooley 7-3, 201-77
USC Pete Carroll 6-6, 77-12
FLORIDA ST Bobby Bowden 5-6, 304-97