The bottom line in all of this is that Dak SEEMED like a kid who "gets it." By that I mean one who understands that asking for ALL the money dooms him to playing on mediocre teams for the duration of his contract, followed by all manner of derision for "underperforming" and "not earning his money" or "not living up to the salary." He seemed like someone who would do his best to stay out that circumstance. If he signs for $25 million a year he will be filthy rich for the rest of his life, assuming he doesn't do anything stupid with that $100 million he will make over the next 4 years.
As the face of the World's most visible franchise he will likely equal that salary in endorsements. If he gets this team to a Super Bowl he will be shopping his services as a pitchman using the name your price tool. Then when he is done playing some network will offer him $20 million a year to be an analyst.. again because he is (was) the QB of the Dallas Cowboys.
So conservatively if he makes $25/year on the field over the next 10 years and $20 million a year in endorsements he will have made $450 million over the next 10 years. Hell even if he only makes $10/year in endorsements he still comes away with $350 million. Flip that and say he gets $40 million/year in Salary.. but the team sucks.. No advertiser is going to want to touch him after a couple of years. So he makes $160 million on the field and maybe 20-25 million total in endorsements before he becomes persona non grata with the ad folks. Playing the "short game" might cost him as much as $200 million dollars vs playing the long game.