http://www.microsoft.com/en-us/news/press/2013/aug13/08-23StatementPR.aspx
Wow, I did not expect this to be honest. Though MS didn't really take the mobile market by storm... could it be because of that?
I wonder who will become the new CEO? An outsider?
A multitude of reasons.
Now, to be fair to Ballmer, MS's revenues have increased exponentially. The problem is that it's more a natural progression of their traditional markets like Office and Windows OS than anything Ballmer did.
Let's look at everything else that has happened under Ballmer.
Portable Music Player - Everything MS did was a disaster or barely affected the market at all. Plays For Sure? Zune? Yeah...that really killed the iPod.
Xbox - Most of the early success was under Billy G's reign. The Xbox One has been a PR disaster so far. It's a salvageable situation but Sony looks to be the king of the next gen of consoles. The only consolation is that Nintendo shot themselves in the foot with the Wii U.
Phones - Let's face it, Windows Mobile had a decent market share when the iPhone just came on the market. Android was not out yet. MS had a chance to really take the market by piggy backing on the hype created by the iPhone. We all know how that went and Windows Phone (the successor to Windows Mobile) has been irrelevant for the most part.
Tablets - Tablet PC's have been around forever really. They are kind of an extension of laptops. I remember using a touch based Windows tablet years before the iPad came out. This niche is now dominated by Apple and Android. Seriously, Apple and Android should NEVER have eaten MS's lunch in this area.
Windows Vista - I'm not going to call Vista a failure but it wasn't good PR wise for MS. I always thought this OS got short changed. Most of Vista's problems was due to hardware OEM's pressuring MS to lower the "Vista Ready" specs so many people who upgraded were stuck with slow PC's that weren't really Vista Ready. Peripheral makers also had a lot of problems getting Vista drivers out so a lot of devices did not work out of the gate with Vista. This put a lot of the blame on Vista because the end user doesn't know/care what the problem is. All they know is their printer or whatever worked in Windows XP but it doesn't in Vista.
Windows 8 - Puzzling OS. Lots of good, coupled with one idiotic design decision. There are lots of under the hood refinements in the OS. The problem is some of the UI elements that FORCE you to use touch or gesture based controls when you don't want to. The removal of the Start Menu didn't help. All they had to do was allow you the choice to use a traditional UI that you've been using for the last 20+ years or a touch based one.
If you go down the list (not just what I listed), MS has failed at practically every single new market it has tried to enter.