It's in a different league in terms of size, at this point.

Also, FB bought Oculus. It has grown since, but most of where they are is on trajectory from the purchase. Meanwhile, VR as a whole is neither a big not profitable market. The competition are also a bunch of upstart-ey businesses/divisions limited by investor generosity.

Zuck makes good acquisitions, no doubt about that, but Oculus isn't an Xbox yet.

Xbox, OTOH, is proof that Microsoft could enter a completely different market, compete, win and create a whole new business division. It was already a mature market.