I don't have the Kurt Warner video someone posted last season where Kurt dissected Dak's passing game. In the video Kurt showed how Dak was not seeing the defense and he was throwing to the wrong receivers. Of course all these videos select plays that help make the argument the presenter wants to make. But Warner's video, I thought, was very insightful.
I think it is obvious that the biggest difference between Dak and Rush is that Rush sees the defense and has a better idea of where to throw the football than Dak does. Call it knowing the offense better, or whatever. But Dak is less decisive in his throws and seems more confused by certain defenses. You cannot blame Moore and the receivers for every bad play. I am sure they make mistakes while Cooper Rush is playing too.
I am not suggesting Rush should be the starter. There is a reason Rush, missing some players on offense, has won 3 games this season alone. We have seen Rush make some good plays and avoid mistakes. But we have seen Dak put up way more points in games than Rush seems capable of. Dak should be the starter. Rush has just been surprisingly good while he has played.