It's a fair point and well put, but I think there are divisions within the Wenger Out camp. A lot of them have had it so good, for so long - in some case their whole football-supporting lives - that they are in for a rude awakening when he leaves, and they experience the wilderness for the first time.
In recent seasons, Arsenal have splashed a bit of serious cash, but so have four or five other sides. For the majority of his tenure, when a lot of the grumbles started, he's had them punching above their financial weight. He's not perfect, and I don't think it's unreasonable to want a change, but I wouldn't personally if I were an Arsenal fan.