I've always said Dak is a "momentum" player- that is, he plays well when things are going well.
But if you watch his film from college he is exactly the same;
He does great when things are going great, but when he feels pressure he is the first to choke.
He was in his element in 2016, standing behind the best line in the NFL with all day to throw and with opposing defenses focused on Zeke.
But when that big offensive line grew weaker as their prime passed and injuries took their toll, Dak was just Dak. No better, no worse than he was in college.