As a former coach (certainly not anywhere near the NFL level

), I will tell you there is no such thing as winning a championship by being lucky or riding the coattails of players. That may be true in regular season sometimes when teams play inferior opponents, but in the playoffs, etc., that would be exposed.
Throughout the years I have seen teams with great players that never really lived up to their potential. I also have seen some mediocre teams (personnel-wise) rise for the occasion and win the big game. Being a successful coach takes a lot of work and people who have never done it mostly do not realize all the nuances of coaching.
Billick may have been at the right place at the right time, but don't understate his coaching ability. He did a wonderful job in the Super Bowl season and overall, he did well throughout the years in Baltimore. I know he wasn't perfect, but he was a damn good coach. I do wonder if he would want to coach anymore though. He seems to be doing well at Fox.