From a football perspective, you ask a great question.
The decission makers are CU Chancellor Phil DiStephano, President Bruce Benson, and the elected regents.
If the decision were up to AD Mike Bohn, Dan Hawkins probably would have been gone after the 2009 Nebraska game, with a slight possibility of keeping his powder dry until the Pac12 decission.
The Regents, President Benson, and Phil DiStephano have relegated football success as "nice to have", not "must have." This drives the CU football fans nuts. Bruce Benson is on record saying that Dan Hawkins will be evaluated at the end of the year. He prides himself as an academics first chancellor and a man who stands by his word.
Denver based President Bruce Benson let's Phil DiStephano call the shots in Boulder, but will veto a buy-out if it gets in the way of politics around higher ed funding.
The Regents won't pull the rug out from under Benson or DiStephano on something as seemingly trivial as college football.
It must be really hard for someone from Nebraska to understand that the U of Colorado takes it's academic mission more seriously than sports-entertainment.