Their thinking is that this approach worked with PCs, and that the overarching software license/hardware partner strategy will not change for smartphones.

"Microsoft is best served doing what it does well, which is software," says veteran tech analyst Roger Kay. "Acquiring a hardware company can provide great integration and an element of control, and Apple has excelled at this, but with Microsoft it could be a big distraction from its main business."

Microsoft does not have a good history with mobile hardware purchases. Its $500 million acquisition of Danger Inc. in 2008 -- Danger was the maker of T-Mobile's Sidekick phones -- resulted in the very short-lived social media-centered Kin phones, after a mere six weeks on the market.

When Microsoft tried to develop its own hardware, as with the Zune media players, success had eluded the company as well. However, you could call Zune players a noble failure and a victim of Apple iPod dominance in the MP3 player space, not necessarily a condemnation of Microsoft's product design or development.

Nevertheless, being a hardware vendor is outside of Microsoft's skill set, says Kay, and is a risky business in general.