Re: Making money is one thing...
Your statement "generating a steady revenue, that's the real challenge" is surely true, but even the best manager can't maintain a monopolistic revenue stream forever.
The only way forward is to hold on to the monopoly as long as possible -- and that is something Ballmer did quite well (see 1st comment for the sentiment he earned for this). Once the monopoly is gone, the extraordinary earnings will be replaced with quite ordinary earnings. The big question is whether the company can survive without the monopoly.