Yeah, because he couldn't practice with his team. Doesn't matter, none of these could walk into a huddle and have immediate success. I would think he intended that to mean that the QB isn't defined by his system. Of course if a QB doesn't know the plays, terminology, etc., he won't have success. Any of those QBs could have success in any type of system, as he explained. I know the one sentence you're focusing on from his article and, if he meant it completely literally, then I disagree with him. It's going to take some time for any QB to learn plays and terminology, but there's not a system in the league that Peyton, Brees, etc. couldn't excel in.