Well I'm not entirely sure about that. The club has only just seen some stable growth under Pellegrini, if they start overburdening with internal conflict and "punish" their player they could have another loose-cannon Tevez situation on their hands. Strong-arming an unhappy player almost never works out well. For Athletic Club it pushed out Llorente on a free transfer. For United, they folded and now have Rooney getting whatever he wants whenever he asks for it.
They could do good business by selling Yaya to a fellow money-club for a steep price and use that to help fund transfers under their FFP sanctions. At 31 he isn't getting any younger and they could pursue a younger player of a similar mould if needed (I could definitely picture them splashing the cash for Pogba and him agreeing because he wants the money and to spite United
)