Why work now, and essentially work for free? Actually, work for a net loss, when you consider the cost of relocation? Since his payout from Auburn is reduced by whatever his new salary is, there is no near-term financial incentive for him to move on.
(At least, that is my understanding of the terms in the Chiz contract - did Tubs have something similar, or was he paid-in-full prior to taking the TT job?)