Decoy, I completely agree that most successful coaches identify an issue, find its' origin (technique, personnel, staff, scheme, etc.) and correct. Given that this Coach hand-selected the staff and has steadfastly stood by them for 4 years, it is hard to argue that he even recognizes that a problem exists. Remember, this is a "good team" that is "close" and just seems to be stuck in the "same movie". In other words, NU is a victim of circumstance with no ability to re-shape the outcome (with sarcasm of course).
That then leads me to the conclusion that staff changes at this late stage are only the result of booster, administration, or fan pressure and are a means to prolonging tenure. The changes will not ultimately result in a better record next season.