You've got to remember building the Emiretes meant Arsenal have taken a financial hit whilst also having a big wage bill. Than take into account, the club is run properly. It would be a huge help when the FFP rules kick in, at the moment it seems Wenger is willing to put the club trough some austerity for the long term.
Fans like to act dickish regarding spending money though, I know Swansea City fans who think we should spend £8 million on a single player thus ignoring the real economic implications. It's easy to say Arsenal have £70 million to spend but running costs and bonuses will eat up a chuck of that.