> Seems that Sidekick and Kin are counter-examples to that statement.

Microsoft threw away the working Sidekick OS and re-built it from the ground up on Win CE so that they could brand KIN as a "Windows Phone". So isn't that really a perfect example?

Exactly. Sidekick was thrown into the trash before the customers even knew it, and Kin was pitched into the dumpster before the launch party was even over.

The only non-Microsoft brand to come out of Microsoft is, curiously, the XBox.

Isn't it the "microsoft xbox"? I mean, everyone knows it's microsoft's (and it's printed on the game boxes)... No?

Huh? Sidekick was a well established preexisting brand.

Yes, and they threw it out. It's Microsoft or the highway.

In addition, with all the semi-frequent frenzied branding changes, Microsoft leadership seems to be acutely aware that they lack a well-regarded image with the consumer market. Perhaps they would decide against such a strategy, but "never" is a bit extreme.

As far as the carrier issue, let's just say XCom Global and the individual carriers all snub Facebook. Even without Microsoft, Facebook has more than enough cash on hand to directly buy out Sprint Nextel and/or its assets. A foothold in the US alone would be a strong enough starting position to make this feasible.