The Dolphins absolutely could not "have gotten Kyler Murray for nothing."
Kyler Murray (and Tua, for that matter) had 100% control over which offer they chose to accept, and given that they definitely weren't getting any pay raise for the 2026 season, that choice was entirely based on the promise of the team offering.
Zero chance Murray chooses to play in MIA over MIN for the same money. None.
Maybe, maybe not.
I agree Murray had 100% control where he went. And I agree that no team could offer him extra money to attract him.
But it is possible that if the Dolphins had offered Murray a contract and a promise to at being the starting QB, he would have chosen that over competing with McCarthy and Wenz for the starting job in Minn. Vikings offers him a better chance at winning and getting a ring. Dolphins would have offered him a better chance at being on the field. As it turns out Vikings gave him both, but no way he would have known that in the off-season.