There are so many reasons why the Gase success was no mirage...
1. Over coming a 1-4 start.
(Proving even at it's worst point, he never lost the team)
2. Getting into a huge winning streak when they needed it most.
(Proving that the culture of the team was already changing)
3. Winning most of those games during the winning streak normally at the end.
(Proving one of the biggest changes was, there was no longer any quit in this team)
4. Winning games without one of their best defensive players in Jones, injuries to the corner position all year, losing one of their best Linemen in Pouncey for the year, no real starting talent at LB other then Alonzo thanks to injuries, and losing a very hot starting QB for the last few games of the season.
(Proving there was never any panic in Miami, just a next man up mentality)
5. From day one, players no longer played as individuals, and all were held to high expectation at practice as well as games, if you did not produce, you were let go.
(Proving that the mentality of the team was now to play as one, and each held to high expectations for the others as well as themselves)
Each of those proved how well Gase was able to turn the mindset of a team that only a year ago would have given up after starting 1-4, would have normally lost if in a close game, would have started to show panic if the injuries started to pile up, but to me, one of the biggest indication of why Gase will not fail, happened in the Jets 2nd game.
Miami is pretty much crushing the Jets late in the 4th quarter, Moore throws a deep pass, and misses the completion, Gase on the sidelines was going crazy, he looked beyond upset. During the whole season he was like that when Miami won, and you could see that he was not satisfied, because the only things that seem to stick with him in the games was the moments of failure. To Gase, winning games comes 2nd to playing like a championship team (Mistake free)... and that is how championship teams are Built.