What?
Sinofsky was reporting directly to Ballmer before his resignation. If he was fired, of course Ballmer fired him himself. Sinofsky was his direct report.
People only report directly to the CEO because they are seen as capable of acting largely with autonomy. It's a sign of trust, not incompetence.
The conclusion that Ballmer would micromanage Larson-Greene is absurd. He doesn't have the technical chops. The suggestion that he would do so with Reller, ignores her demonstrated professional competence.
The most likely case is that Sinofsky is gone so that they could be promoted. This probably wasn't a crisis, but something brewing for a long time. The issues with Office under Windows 8 RT were due to structural issues with Sinofsky's management approach.
It's the "Clearly" that makes it sexist.
Point out the sexism.
CEO is female and product heads are male, point out the sexism CEO is male and product heads are male, point out the sexism.
CEO is male, product heads are female. Without any more information then that, you saw sexism. Point out the issue. You are making huge leaps to conclusions that are just not supported by the information given.
It only implies removal of a layer of management if one doesn't see Reller and Larson-Greene as having been promoted.
The appearance of Larson-Green and Reller on Microsoft's Senior Leadership Page supports my thesis.
The sexism upon which this statement is partially premised aside...
I have an entirely different take on this promotion. Microsoft has been run by a pair of consuls, Ballmer and Gates, for a long time. One focused primarily on the business side, the other upon the technology.
At this point it is only prudent for them to look at leadership succession. Larson-Greene has real technical chops and has worked on compilers, Office, UX, and Windows. Teller went from receptionist to CFO at Great Plains, leading them through both an IPO and Microsoft's acquisition.
It is clear that the future leaders will be from the post IPO generation of Softies. It may be clear now that the tradional pointed elbows approach to the throne is frowned upon.