Thing is, his being up has almost surpassed. The guys in his draft year all have been paid that are going to be. Mahomes and Watson already have been as well. Josh Allen and Lamar Jackson are the guys coming up and Dak doesn't deserve any more than either of them. There is also Mayfield. The reality is that Dak as it stands is no better than the 8-12 range as far as QBs go. He's not better than Rogers, Brees or Brady. There are a handful that you can argue he is in the same group as....that aren't coming off a serious injury.
Dak played one year on his rookie deal when he could have signed a contract similar to the deal Wentz did. He played on the franchise tag when he could have been paid more on a long term deal. He has left millions of the negotiating table and I doubt that he ever makes that up.
Dallas always has the choice to let him walk as a free agent and tell him to bring his best offer and they will decide whether they will beat it or not. If that happens, Dallas would certainly get a 3rd round comp pick for Dak and a lot of cap space. And we would see what Dak's value on the market is. Of course there is always a team or two that will screw up the position range by overpaying someone.