He doesnt have to, however, the optic that gives, is that he's not particularly interested in winning. If he thinks the heat and public opinion has turned over the last couple of years then a Rinse Cowboys contract (on his terms), would create such pressure FOR HIM TO PLAY UP TO THE CONTRACT that's its tantamount to his part in the play-off failures, a lack of composure when pressures on his game.
As for managing the CAP, I assume the sticking point is the number of years....especially with the $40M restructured money.