The idea that certain former blueblood schools are still attractive, job-wise, is one of the classic misguided tropes of our time.
For instance, there are four schools, off the top of my head--Michigan, Tennessee, Nebraska, UCLA (and of course, numerous others, I'm sure)--where the media and talking heads all go, "They'll be lining up in Ann Arbor/Lincoln/Knoxville/Westwood/etc. for a shot at THAT job!"
A Nebraska fan looks in the mirror and mistakes a tired, beat-up, gray, shriveled shell of a program and somehow sees the equivalent of Bama or Clemson. A Michigan fan sees three straight years of 9-3 or 10-2, without a win against O$U, and acts as if Bo beat Woody every time they played. A Tennessee fan base saw Greg Schiano as evil incarnate due to the massive log in their own eye, as the Good Book talks about.
In other words, the Michigan job has outdated, unrealistic expectations based on the state of that program in 1988 or 1997. The expectations no longer match the commitment and reality of the program. ISU and Ames may be a lot closer to the Ohio in which Campbell grew up than Michigan and Ann Arbor will ever be.