I think something else that muddies the waters as far as evaluating both Ferentz and Iowa as a program is that we are in the unprecedented situation of having 2 coaches since 1979. A lot's changed in the world of college football since 1979.
We know the program had fallen on hard times post-Evy. I think we hit .500 only once in that post-Evy, pre-Fry era. Fry very clearly got the program winning at a, relatively speaking, significantly higher percentage. I can't remember who (but thank you to that mystery poster), but another poster recently pointed out to me that Commings had attracted some good talent in the years immediately prior to Fry's hiring. I looked into it a bit and I believe there is some truth to it - Fry had some immediate success and, indeed, several key components were Commings recruits. Obviously, Fry sustained a level of success (through multiple up/down cycles) after Comming's players were long gone, so I don't think you can make too much of this other than Hayden had a bit more of a leg up on doing what he did than it might seem at first glance but, for me, that really doesn't significantly shift my opinions of what Fry achieved here.
So, you have the Fry resume that's pretty well known, basically spanning the 80s and 90s. A couple peaks, a couple valleys, none of which are what you'd call sustained. The important takeaway is that it was two decades worth of Iowa football that were, in the context of the overall program history, a bit above average (in the context of the previous 2 decades prior to Fry's arrival, I'd say they were "well above average").
That brings us to, what for me, is a very instructional time period in program history - the Fry to Ferentz hand off. For me, this runs from 1997-2001 (Fry's last winning season to Ferentz's first). 1998 and 2000 were not great years, but aren't really outliers as far as either (a) what "down years" have looked like in the Fry/Ferentz era and (b) what truly *bad* seasons have looked like for Iowa historically. For a modern Hawk fan (who, with apologies to a couple of the old timers here, almost certainly doesn't remember Evy and probably remembers very little - if anything - pre-Fry) to really understand what Iowa playing *truly bad* football looks like over the last 40 seasons, if you don't remember it (I do, unfortunately) or it has gotten foggy for, you really need to go back and look at that 1999 season.
That is what the Iowa football program looks like when it's not being properly fed and cared for. It happened alarmingly quickly, too. You went from a 1997 team that, on the basis of a very good 1996, was expected to compete for a Big Ten title to, two years later, the worst season of Iowa football since the Frank X. Laterbur train wreck.
Of course we know now that Fry was (privately) struggling with very serious health issues over this era so, by his own acknowledgement, the great man's accelerator was not all the way to the floor. Look at how quickly and low the program fell, just like that.
From there, we have the Ferentz era. This is even more fresh and I think most of us are well acquainted with both the highs and lows. Obviously, just like under Fry's 2 decade reign, the college football landscape has shifted throughout Ferentz's 2 decades as well. Is Ferentz the absolute best Iowa can do? Of course not. For starters, Nick Saban exists. Beyond that, due to the randomness of the universe, it's probably pretty safe to say that the theoretical best college football coach to have ever walked the face of the earth has never even seen a game of football! You have to temper your expectations with the reality of knowing you're trying to do the best with what you, at a given point in time and space, can get your hands on. There are better football coaches than Kirk Ferentz (no shit), but they're not exactly falling out of trees.
If you were to let Ferentz go at the end of any given season, you'd have a matter of weeks to find a replacement (a coaching switch is a nightmare in terms of recruiting under even the best of circumstances). You'd need, within those few weeks, to hire a coach that - ideally - would out perform the last one. You're not hiring Nick Saban and you don't have the time to look through 8 billion candidates to find that theoretical unicorn. You need to hire someone - here and now - who is both a fit and willing to take the job. Be honest with yourself, if that's your ass on the line - your reputation, your money - what is your confidence level? Yeah, I know, back to back fullback dives, we're all just beside ourselves. But NY6 bowls. Packed stadium. Big time upsets with the college football world watching. For the most part, great kids and coaches who really care about them as people (I know, Doyle, but he's gone). More wins than losses is very nearly a lead pipe lock for 40 fucking years.
On the other hand, 1999. Frank X. Laterbur. Weigh one hand and then weigh the other. Be honest. If your ass was on the line, would you make the call? I'm guessing some of you would, but that's why such decisions are left to highly paid professionals and not mouth breathing HN trolls.
By the way, none of this armchair program analysis is purely finger in the wind. I've done relatively extensive research into Iowa's historical program performance using Massey data. False humility aside, I have a much better (and objective) appreciation of the overall 120+ year program arc than the overwhelming majority of fans (even hard core ones).