Grier is the equivalent of a front office "journeyman" who's more than Peter Principle'd out. If not convenient to serve as Tannenbum's useful idiot, he'd still be making mediocre college level talent judgments until a good GM was allowed to come in and clear house.
Tannenbum? He's the cancer from within. Willing to take a demotion to Capologist for the NYJ if incoming replacements didn't express discomfort with him still being in the building, no one else in the collective wisdom of the league wanted any part of him until Ross went dumpster diving. Can you imagine a Fortune 500 company hiring even a manager from a competing company that left them in shambles... not to mention actually promoting him to that division's highest echelon? Un****ingreal! Yes, Ross, hired someone to run the organization who was viewed by the Jets as the equivalent of Dawn Apponte.
The recycling continues…keep hiring the same old guys year after year.