Mike Shanahan's coaching has nothing to do with the Broncos record. If any one person can be given credit for this team's success, it is Champ Bailey who is bailing (no pun intended) out his coach on a regular basis.
Week 2 vs San Diego: Champ Bailey intercepts a Drew Brees pass and takes in 25 yards the other way for a touchdown. Denver wins 20-17.
Week 12 at Dallas: Champ Bailey intercepts a Drew Bledsoe pass and goes 65 yards for a touchdown. Denver wins 24-21 in overtime.
Week 14 at Baltimore: With the ball on the Denver 15 Kyle Boller throws a pass to Champ Bailey at the Denver 6 yard line killing a drive that would have resulted in a field goal. Denver wins 12-10.
Without these three plays by one player, the Denver Broncos are 7-6 and not 10-3.
We should also take a look at the actions of Ian Gold in Week 5 against Washington. With less than two minutes in the game, Ian Gold tips a pass intended for an otherwise open Washington receiver on a two point conversion that would have tied the game. Denver wins 21-19.
Without that play, Denver is 9-4 or possibly even 6-7.
You may ask, what's the point of this? You can't play hypotheticals, these things happened, blah blah blah. Here is your point. If you remove four plays from the Denver Broncos season, they have a losing record. FOUR PLAYS. We're not talking about a multistage process here, we're talking about removing four plays. Shanahan is doing a horrible job coaching this team, but he's been bailed out on several occasions. Good teams don't rely upon luck to win. This kind of play doesn't win playoff games and most certainly doesn't win championships.