Did you ever think that maybe those coaches you mentioned learned something in their previous experiences that helped them in their next job? Maybe after being fired, they adjusted their approach in certain ways? Or maybe it just means someone like Dungy was a good coach, and was able to get paired with a great QB and win a title? None of this proves that Philbin is a great coach now, or that he will ever turn into one.
The coaches needed to get that first job to learn how to coach. Rarely to first time coaches succeed long term with their first head coaching job.