I don't think they look at player personnel, at least when it comes to FA, through the prism of position needs or overall team needs. They just look at players. They just want to grab bodies, especially their own, in FA.
Randy Gregory is a good DE. He's not a great DE. He was offered $70 million which is a pretty large contract for a DE. That kind of contract would give you the impression that the Cowboys realize they have a big need at DE opposite Lawrence. And yet, when Gregory bolts, they make no moves to land an equally talented or better DE. That $70 million "budgeted" for DE vaporizes. Because it wasn't budgeted for a high level DE. It was just budgeted for Gregory. They signed a couple of cheapies and move onto the draft. They didn't slot $70 million to get better (or at least not regress) at DE. They just slotted the money for Gregory, only.
Take Elliott. They paid him a massive contract. One would think that it's because they view the importance of a TB to this offense, hence why they paid a talented TB all that money. But if Elliott could retire tomorrow with no cap implications for the Cowboys and Henry or Kamara or Cook were free agents, would the Cowboys spend that kind of money on talented TBs to replace him? Nope.
What we are seeing is a disconnect between what they are willing to pay their own players that they like and what they are willing to pay to fill the position if "their" player left or wasn't here.