If Jerry really wanted Dak, he would be signed already to some monster contract that the team can't afford.
It is wise considering salary cap ramifications but stop applying that consideration onto Jerry Jones. His way of thinking is not the same as yours, mine or others.
Jones will do whatever he can in getting whatever he wants if it within his power to obtain it. And he quantifies his actions by the way he thinks. Here is Jones explaining his 'all-in' nonsense
(link):
"I'm into it here. I'm all in. I'm all in. Sometimes being all in means you narrow. You remove the months out here that are in the future. And you narrow it down to where all we're talking about is right now and the next playoff season. And that's it for everybody," he said.
[Jones translator]: "My focus is right now--not months into the future. My focus is
eventually securing players
I believe will help us win in the regular season and postseason. My focus is
every player
I am either targeting right now or will become a target after
I believe the need should be addressed."
This is only a suggestion. Jones really wanted CeeDee Lamb. He
eventually signed Lamb. It is EXTREMELY probable Jones really wants Dak Prescott based upon his decades long tendencies per the position.
Take the time that has elapsed for signing Prescott out of your assumptions. Time does not matter one iota to Jones.