Buyouts are total false sense of security, Beilien paid at least part of his own 2+ million buyout just to escape Appalachia!
Only the truly ego driven coaches (Coach K, Stoops, etc) really care about the money once it reaches this level - it is many more times about the support of the AD, etc.
As sys said, the buyout money would be nice for the next coach, but in the two highest profile buyout situations I can remember (Beilien and Rodriguez leaving WVU to UM), they both ended up in court anyways, reducing the actual financial benefit of the buyout.
I think it is not a coincidence that Frank go paid almost identical to Anderson at MU - I think that was part of his ego not wanting to be paid less than a guy he doesn't like (and maybe doesn't respect?)