With tax rates, a hundred grand a year is really only just over half that in hand, and when that is on top of an income of hundreds of thousands, the extra bit won't make a big difference to life style.
I reckon the "extra" is as much about status to a young player like Bird. As is the position on the field that he plays.
Staying near home, with his mates, and the team he won with, would all help, but we need to make Bird feel as special as the Broncos and Knights are trying to.
Maybe tell him we are grooming him to replace Gallen, an all time Sharks legend that he surely respects as much as anyone, though he'll have a more roving role, and put him in a "leadership group" with Graham and Maloney. Let him talk at some press conferences if he wants to. Let him think he could be a long term legend, one team player, and eventual captain, of a premiership heavyweight, surpassing even Gal if his form holds true for his career.
Remind him that many great, experienced players, like Maloney, Ennis, and Lewis, have shown their best form with this coach and with this team, so staying part of that system is his best bet at long term success.
Oh, and name one of our bloody towers after him, and give him the top floor....