I have time to break this down now.
Gene Chizik - DC for Texas and won a national championship. Many called this hire huge. Turned out he couldn't coach a lick. Without Cam Newton, he was 19-19 at Auburn, going 0-8 in his last season. The very next year, Guz Malzahn took Auburn to the National Championship game. Most everyone in the country agrees that Chizik is a bad head choach.
Dan McCarney - 12 years at Iowa State. Had some decent offenses. Had some decent defenses. Never really at the same time. Beat the teams he should have beat. Rarely beat someone he shouldn't have beat. Ended his career 56-85 at ISU. First bowl win in program history.
Jim Walden - Hired in 1987 away from Washington State, another school with similar Iowa State history. Had 1 bowl season at WSU. Overall, was not a successful coach coming into ISU or leaving ISU.
Jim Criner - Came from a very successful run at Boise State where he won 1 now called FCS National Championship and made the semi's the next year. He went 4-7, 2-7-2, 5-6, and 6-5. But was fired for NCAA violations.
Donnie Duncan - Similar to Gene Chizik. Came in from Oklahoma under Barry Switzer. Overall, wasn't a good coach. Was never a head coach anywhere else after Iowa State.
So of the coaches in the last 35 years, sans Paul Rhoads, 1 was only a HC for Iowa State, 2 never got jobs after Iowa State, and 2 were hired after leaving Iowa State.
Of those coaches, I know we have hindsight now, but really only 1 maybe 2 would you think were sure fire good hires that should have worked out. Chizik and Criner. Chizik was incredibly successful at Texas at DC and was known as a great recruiter. Later, everyone found out he was a crap HC unless he had Cam Newton and Gus Malzahn calling the plays. Criner came in after a pretty successful run at Division 1-AA Boise State but was fired after NCAA violations. I'm not old enough to have watched those teams to know what they looked like so maybe someone older can comment on how those teams looked and maybe comment on if it looked like the program was turning the corner.
To the people asking to point out a successful head coach at Iowa State in the last 35 years, I'd tell you we haven't had one. But we also have only made 1 great/good looking hire in Chizik. Otherwise, we have hired crap coaches or just mediocre ones.