Game makers and Microsoft both were annoyed at supporting the diversity of PC gaming hardware. The Xbox was Microsoft making a console out of PC hardware, basically. Vastly over-simplifying it, of course. And yes, it ran at a loss for years.
And we also know that Valve *really* does not like the prospect of PC gaming under Windows 8. Microsoft might not, either, TBH but I haven't heard anything in the press that says they have even voiced an opinion. They've always liked the closed-ecosystem that a gaming console provides.
Wade.