Let me start by saying that Saban is arguably the greatest coach in the history of college football. With that said, I don't think anyone has ever been more fortunate as hes has been in his career. Let's take a look at his National Championships.
2003 LSU - Instead of playing the #1 team in both polls (USC) his team gets to play an OU team coming off a 35-7 loss to Kansas State in the Big 12 Championship game. Not his fault, but still a split championship that was most likely only awarded because the Coach's Poll was contractually obligated to crown the winner of the BCS as national champion.
2009 Alabama - Colt McCoy leaves the game in the first drive. True freshman Garrett Gilbert has Texas within 24-21 with the ball late in the 4th quarter before falling short. Injuries are part of the game, but another lucky break.
2011 Alabama - Does not win their own division after losing at home to LSU. Gets the championship berth over Oklahoma State, and wins a rematch against the team that won the SEC West, SEC Conference, and head-to-head match up in Tuscaloosa.
2012 Alabama - Dominates an over matched Notre Dame team as the #2 team in the BCS Championship Game. However, Ohio State completes an undefeated season and is under post season probation. Had Ohio State not appealed their bowl ban the year before, there is a 0% chance that a 1 loss Alabama team would have been selected over them or Notre Dame.
2015 Alabama - Wins the playoff over #1 Clemson in a classic. No disputing anything about this one.
2017 Alabama - Gets the 4th playoff spot despite once again, not winning their own division or conference.
The fact that his teams are always in the conversation is what makes him an all time great (perhaps the greatest). However he is definitely one lucky guy that has benefited from the SEC bias.