In most cases in terms of players, it was purely financial. Tenn refused to pay Brown what he wanted. Giants didn't want to pay Barkley what Philly gave him.
It wasn't a financial decision for the Steelers. They had grown tired of his antics, which are WELL documented. Tomlin literally called him out in a press conference.
Again pretending that this isn't a thing with Pickens is strange. Hope it works out and I might have more faith if we had an organization that has a track record of reigning these types in but sadly, we are not that kind of franchise.