There are countless contracts that were renewed based on the magnitude of the fight In question.
A lot of fighters end up with bum contracts It seems or contracts that are far less than Ideal over time due to their evolving situation.
It's definitely not as simple as "you signed the contract, live with It" Especially In this case, where It would essentially be a champ vs champ fight.
At the end of the day, money and business Is half the battle and often It has nothing to do with ducking.
Any time someone wants a pay upgrade, contract negotiation, to be paid their worth or whatever..people these days are too happy to scream duck, which is quite far from the truth.