Bro, i'm tired of saying the same thing over and over but I can guarantee you that every QB in the NFL from Cooper Rush to Brandon Weeden can make beautiful throws now and then but the reason they "suck" is because they can't consistently make those throws game in and game out.
That is the problem with Dak. He is very inconsistent. He could throw a dime one play and miss a wide open check down on the next ...
No different from the Nick Foles and thr Brandon Weedens of the world..
This is why they are career backups. You just hope that if they have to play, they have one of their good days...
Unless Dak magically becomes a consistent good passer, he is destined to become a career backup.