We hear a lot about managers losing the dressing room and not having the players' respect but its obviously not the case with Wenger. The biggest players at the club obviously still see him as a key figure and its a dilema for the board. You either keep the over the hill manager AND your best players or risk losing all and starting from scratch. Im all for change and a fresh start under a new manager but if we were to lose Wenger and Sanchez/Ozil and potentlially others then it would take usa few years to start challenging again (see Man u last 4 years).
Since Fergie left, United have won one Fa cup, we have won two FA cups. We have qualified for the CL two times more than them, then been knocked out in the first round of knock-out stages , they got to the qf once. There's hardly much difference in achievements really.