I disagree. The worst case scenario basically involves what you are saying. For example, lets say the following happens
We hire Key, keep the defensive staff, and bring in a new offensive staff. However, the offense still struggles as it has the past 4 years, and the defense regresses to the mean with respects to turnovers and has some key losses to being back to closer to what it was the past 3 years (and what we have seen against better teams this year at times), and we go back to being a 3-9 team. Then we are the laughing stock who decided to fire a coach and AD mid year just to keep most of the staff and still get terrible results.
I really do not understand the love for Key. Pitt was a great game. Beyond the change at kickers, which I'm not sure we wouldn't have done anyways as it wasn't like the old kicker was entrenched as a multi year starter, I doubt it had much to do with anything he did during the 4 days after Collins got fired and was more just to general relief of not being under the cloud of a coach about to be fired. Since then we've had a mediocre showing against Duke and then three bad performances coming off a bye week. You would expect that we'd continue to improve as more time has gone away but we haven't.