It was a pretty major drop, but a lot of teams are simply not equipped to or don't want to deal with extra baggage. Failed drug screens put the player in jeopardy as far as reliability and couple that with that he is difficult to figure out, most just don't have time for that. Dallas apparently does not mind trying to be a halfway house. They just have to maintain the balance.
They are right about at the limit where they can handle the issues and distractions. There does seem to be a difference between this and the Pacman Jones/Tank Johnson/Terrell Owens cocktail as most do not seem to be "bad people" but there is a lot of maintenance and babysitting required.