In order for Xbox to be a loss leader, it would have to be drawing people in to the platform.
But it isn't doing that any more, people only use Windows due to inertia and because it's bundled with the hardware they bought. And that bundling is anticompetitive because it's arranged through the usual coercion, where the computer companies can't afford to stop buying the licenses.
Windows games have a slight effect on loyalty for home users, but they don't really matter so much to Microsoft any more. Windows is less than 10% of their income now, just like gaming GPUs are [way] less than 10% of Nvidia's revenues* so Microsoft doesn't actually care about the desktop very much in general. As well, the home desktop is no longer important to their control of the corporate desktop, because of lock-in. They don't need familiarity at home, so they really don't care about home users.
* This was true before the circular financing. You might reasonably argue that their doing that cancels out their enterprise GPU profits since they're not getting that money back... but if you don't, then gaming revenue is just noise.