I think it was a mixed bag of problems. We had an AD that simply didn't care enough to invest in the program what it needed, and Criner did Criner things and really put ISU in a hole, so many of Walden's complaints and excuses were valid. And perhaps had Walden coached ISU 10 years later he would have been given more leeway because he did get ISU to mediocre and would have taken ISU to some low-tier bowl games as a result, much like McCarney did... but at the same time he wasn't some savior of ISU football, either. The big difference between Walden and McCarney is while Walden was all too willing to lay the blame of his shortcomings on the university he was coaching at (and, as I said, those complaints aren't entirely wrong), McCarney instead took responsibility for his own shortcomings. For McCarney, while there was a lot of negative feelings toward him in the mid-late 2000s because he failed to meet expectations after he himself raised the bar of success (especially looking at 2005 and 2006), 20 years later he's looked at much kinder. And while time and perspective helped shift the opinion on Walden as well, I don't think he'll ever be looked at as kindly as McCarney is.
ISU administration started to give a damn when Mac got here. Right away construction of the Jacobsen Building began when Mac started.