He puts up good numbers against bad times, when it doesn't count/garbage time. When his team needs him he fails to deliver, especially against good teams. Come playoff time he completely Vanishes.
Only difference I can figure is AD's peak came with the Bengals, whereas Dak's occured with a Blue Blood/ premier NFL franchise. You switch thier places and AD would be on Speak for yourself, Undisputed and those other shows daily and be discussed as an elite QB.