Thanks for all the hard work and research, seriously. But while I'm not completely sold on Dak, one phrase keeps running through my mind: "There's a first time for everything."
We've seen time and again that players break the mold of what's expected or typical of guys in their exact or similar circumstances. Some guys suddenly get the switch turned on, and it's possible that could happen for Dak, with a new QB coach and OC.
I'm not saying they should pay Dak top money. As you alluded to, the more he gets, the less there is for other talent to help the team win. I'm just saying stats are a funny, unreliable thing, and there's a first time for everything.