I actually don't know how Xbox is doing financially on its own these days, but I doubt it's extremely profitable and has a lot of cash on its own. The consoles usually make the money back over certain period of time from games. Could Xbox survive on its own in that scenario?
As for Bing - it's still losing billions of dollars a year last I checked. So are the Surface tablets, and Skype - well Microsoft paid over $8 billion for Skype, and they're not going to get that money back anytime soon. Hotmail, despite many registered accounts, was pretty dead, and I think only some transitioned to Outlook.com.