Gruden is so overrated as a coach - I'll always be grateful for him bringing one home for Tampa, but he really did win with Dungy's team (as evidenced by how good that defense was in 2002).
Gruden feels like the type that, if he can't figure out how to coach/teach a player, he'll easily give up and fall in love with the next one. We saw this happen a ton after the SB in Tampa - how he coached our various QBs and other offensive players. Part of being a good coach is being a good teacher and getting the most out of your players and I honestly think Gruden is absolutely trash at that.