If there is a principle involved, could be that he's not willing to accept a much smaller cut than Pac would be getting again? Or just knowing that Arum won't pay him what he could or should do. Of course having the huge KO to close the books on their rivalry is something, but we're talking about a prizefighter here. If Bob Arum told him he'd make the fight next and there would be a 50/50 purse split, Marquez would probably sign on that day. Why else fight at all? He has nothing to prove and is an ancient featherweight. Who else can he make close to the money against.