Players don’t just take a pay cut out of the goodness of their hearts and for the sake of the team. Pay cuts happen when a player is not worth his current contract but can sign with the same team for a lower amount that is still above what he would get on the open market if cut. It’s a business decision.
To put numbers to it, and I am making these up, Zeke is owed $10 million if he is on the team next year. He will get $5 million if cut. Nobody else will sign him for more than $3 million. If Zeke takes $6 million to stay in Dallas he comes out ahead but also takes a pay cut.