I think you're exactly right that just because Iowa football sucked before Hayden Fry doesn't mean that we can't have high expectations.
But I also think that just because a team falls short in a given season doesn't mean it has to change philosophy or personnel, especially when that philosophy and personnel has provided the foundation for long-term success. You can have high expectations and be disappointed when they aren't fulfilled without thinking that we need to overhaul the entire system.
I get a lot of my perspective from being good friends with hardcore Nebraska fan and being married to a Florida State alum. Both of those schools had sustained success before they won national titles, but they also had periods of time when they were knocked for not being able to get to the next level. Bobby Bowden couldn't beat Florida or Miami. Tom Osborne chocked in big games. They stayed the course, kept doing what they did well, and as a pair they dominated college football in the 90s. You could tell a similar story about Coach sweater vest over in Columbus.
I realize that losing to Florida on a series of missed field goals is different than losing to Northwestern, but it was also a very different era in college football with much less parity. Regardless, there are only about 10-15 consistently good major college football coaches, and we've got one of them. You can't gloss over a disappointing season, and I hope we don't have another one for awhile. But based on Ferentz's history here I am frankly not that concerned about it in regards to long-term success. We will have other opportunities to be great-- yes, Rose Bowl and/or national-championship caliber great-- because we develop talent as well as anyone and we are competitive with every team we play, game in and game out.