Suppose we had the ability to see into the future. Thus, we could offer a contract worthy of that QB's performance over the length of that contract.
You would want to consider productivity, availability, number of starts, winning percentage, off field behavior, awards, and poise during critical plays. Since you could see in the future you would know all these stats, circumstances and events.
Now, looking at the contracts of all the quarterbacks that played from 2016 to 2020 and their average annual salaries, what would you have paid Dak for his performance in his first four seasons?
Who did he outperform? How many games did these other quarterback play in and start? Over that four year period, which of them had the best winning percentage, completion percentage, INT ratio, passing yards, TD's both passing and running? What were their salaries over that four year period?
Again, how much would you have offered on Dak's contract in 2016? Seriously, when you compare his results to all the other quarterbacks?
I'm not talking about a current contract, I'm asking what Dak's performance over his first four years is worth with respect to the salary structures of that period.
Once you've come up with a number, take that contract offer you propose and subtract 5 million dollars. What is the remainder, how much is left?
According to you, that's what Jerry Jones owes Dak.