Dak is getting high on his own supply.
He's under the illusion or delusion that he is an Elite QB.
He doesn't understand or refuses to understand that Jerry can't and doesn't want to lock up the cap for a QB that has failed to produce any playoff success.
If he signs him to a long term deal not only will it affect the ability to sign or resign players, it will be a disaster too if the team doesn't have any playoff sucess this season.
The fans will be ready to move on from him and resent Dak and Jerry for doing the deal.
Dak isn't a Force Multiplier type QB where he helps elevate the talent around him. He requires superior talent around him to succeed.
Having Dak at such a high cap rate will hurt in getting the talent necessary to help him succeed. So Jerry doesn't want to commit himself to Dak and continue to be a mid level team. He will likely want to go the route of acquiring and keeping superior talent while having a QB who doesn't eat up so much cap space and could possibly give you the same or better results than Dak.