From what I remember, a lot of why Des' re-negotiation with Manly took so long was because the board wanted to take back control of a lot of things, control that Des wasn't prepared to give up.
Money played its part of course, but I reckon one of the main reasons Des took Greenturd's offer to change clubs when he did was because he was offered the same type of control over things there that the Manly board at the time was trying to take from him.
Des went to the Bozo school of coaching. He's the coach, the boss, and if you want to win you do it his way and his way only. He had that at Manly until the board wanted their power back.