Microsoft stock was flat under Ballmer because of hangover from the massive dotcom bust in 2000 and the DOJ consent decree which didn't expire until 2011. It would've been hard for anyone else to do better.
That said, the one thing Ballmer did right is that he took on the difficult problem of locking down Microsoft products on a security front. This was a hard and thankless task, but absolutely necessary in the long run.
He's talking about the TwC initiative, which came from Gates: https://en.wikipedia.org/wiki/Trustworthy_computing. Even after stepping down as CEO, Gates maintained an informal role at MS as an ideas guy for a number of years.
The usual tendency is to give credit to the person who comes up with the idea, and the blame to the person who implements it.
But ideas are a dime a dozen. I give credit not to coming up with the idea, but to actually putting in the elbow grease. And there is no question that Ballmer put a lot of elbow grease into keeping the initiative going.
