Good post. I also think a relatively minor yet important factor is just the exhaustion of starting over. If you are coming off of a Final Four at Illinois and have a top 10 class coming in and Duke comes calling to replace Scheyer because they have missed the Tournament a few years in a row ... do you move if the salary offers are the same? Duke is the unquestionably superior program, but is Illinois good ENOUGH that uprooting your family and building a program back up for a salary Illinois is willing to match? Perhaps the headache of it all counts against Duke, even if Duke is clearly superior on paper.
Additionally, I think some guys like the idea of standing out in a program's history. I absolutely love the guy, but Lou Henson has a court named after him for reaching one Final Four ... he'd blend into the histories of Kansas or Kentucky. The coach who wins Illinois its first National Championship is going to have a damn statue outside SFC one day, haha. Duke fans expect another one in your tenure, or you have failed. All that is to say that coaches take "worse" jobs all the time, I would imagine, for a variety of more subjective factors.