We all realize every championship team gets a few lucky breaks along the way. The football has an unusual shape, and it can bounce in an unpredictable way...that's just the nature of the game. We've been very fortunate that the breaks usually went our way the past five years. But that won't always be the case, see last year's Iron Bowl for example.It's simple, we might not.
Then again, if we struggle on pass defense like we did last year (or in, say, 2010), crazy things can happen even with marginal-at-best quarterbacks. You're rolling along just fine, you show up to play one afternoon, and all of a sudden some career nobody starts doing a Joe Montana impersonation. Those kind of things happen when you aren't up to par defensively.
Ditto on turnovers, too, and QB play of our own. You're playing some barely .500 team that you ought to steamroll, and next thing you know your QB goes 10-20 for 90 yards and you turn it over four times, and suddenly you are in an ugly nailbiter with a team you ought to beat by 24. Again, things like that just happen.
Again, not saying that any of that will happen, just pointing out that it's a feasible possibility, and not a crazy notion.
Saban removes the importance of luck through his preparation, recruiting and general process better than any other coach. But it is still there, and has the ability to bite us when we least expect it.