I take the point that it's hard to discern per platform. The question remains what game sales figures have been announced to further provide evidence of its' viability?
You're making my original point for me again. There's so much more market scale of developing a traditional game over a VR game.
On the topic of 'Microsoft should support VR on Xbox' consoles you can be optimistic, pessimistic or pragmatic.
Pragmatically, I would suggest that a Xbox VR add-on, has a lot more in common with a PSVR add-on over the Quest 2. As such, they can expect similar numbers, which beg the question whether it's worth supporting a tethered, expensive, add-on, with $60 games over a stand-alone product with cheaper games and a lot more 'non-gaming' versatility.