I know some people went into rage mode at the very suggestion that Xbox isn't worth it to Microsoft, but the article does raise some valid points. That Microsoft should abandon the Xbox brand isn't one of them, however. We already know that the brand is a huge part of Microsoft's plans going forward, even to the point of pulling other devices and services under its umbrella. The plans for it are far more ambitious than just a gaming system, as Microsoft wants to use it as a beachhead for taking over entire households. It's kind of a "you already have Xbox, might as well get a Windows Phone and Windows tablet, etc"--a strategy which Apple already uses quite well.
The bad news is that Xbox is probably one of the most viable parts of that scenario. Windows Phone is showing little signs of becoming meaningful and even though Windows 8 sold a lot of licenses and cheap upgrades it's probably still going change little in terms of market share. Microsoft has also had its share of true money sinks, as well, like Zune and Bing.
From what I can see, they can't afford to NOT keep Xbox as one of their flagship programs. It might be the second best leverage they have to get more Microsoft products into people's homes.