i think some people also forget that two times we've won the NC we had to have help from teams in front of us losing to even get the chance.Every year there are examples of unfocused teams going down to far weaker competition even in weaker conferences. Ohio State has provided some examples of that in recent years. Clemson also did in 2017 and 2016 already. We have been blessed (mainly by Saint Saban's training process) to survive some of those close calls on down weeks over the most recent years (albeit in a tougher league).
there's a good bit of luck that goes into winning championships a lot of the time.