You might be right.
Though why does it matter? For whatever reason, he can't win pressure games against good teams. He's had 8 years (well maybe really 7, considering the ankle injury) and he's been consistent only in that - he doesn't play well in big games. And 8 years (actually I said last year the same thing, but I pushed it back since he missed so much time with the ankle) he's had his shot. Just like 10 years with Garrett, at some point you have to make a change, there's no other choice.
Sorry Dak, you're a great guy, you've done well for a 4th round pick, but you're not good enough at playing quarterback in the NFL....