I think it's going a bit far to call him an idiot. He's a numbers droid, all he is interested in is if the money is rolling in, who cares how they achieve that.
Bill Gates was a geek, he cared about products, computers and software. Which is probably why there appeared to be a bit more innovation and leadership back then. Ballmer just reacts to the competition and does what they do as there's a few bucks in it.
He's not in the correct role, he should be their chief financial guy (CFO). They need someone like Jobs or Gates in the CEO role again, someone who has some vision.