To me, the most striking part of this author's argument is that Microsoft isn't prevalent enough. They're still making plenty of money, but he wants them to be chasing the tech press a little more. It's pretty obvious to me: Microsoft isn't in the innovation business just like IBM and GE. They make money hand over fist, but they don't focus on the latest fad of social media or micro-blogging or mobile devices. If those any of those businesses show long term growth and profitability, one of the established leaders will acquire them and I would imagine Microsoft is constantly looking at such businesses for acquisition.
On a side note, I think he's reading into leadership departures in ways that suggest that he has more information regarding them, but he never shows it. An anecdote does not make a trend.