How many QBs will have started all 16 games this season? Not a ton.
Tony Romo, Eli Manning, Jason Campbell, Jay Cutler, Aaron Rodgers, Brett Favre, Drew Brees, Tom Brady, Kyle Orton, Phillip Rivers, Joe Flacco, Carson Palmer, Matt Schaub, David Gerrard, and possibly Peyton Manning, unless they bench him this week (which is a very real possibility).
So only 14 (maybe 15) out of 32 teams had a QB start all 16 games. Therefore MOST teams do not have a QB that starts every game.