Oh I didn't think of Oculus. That makes quite a bit of sense, actually. That would give them a chance to roll their own policy for ads in games, among other things. In combination with VR it will be interesting to see what will come out of that, despite not being part of the target audience myself.
The problem is that Oculus is not hugely popular and faces stiff competition from other VR hardware. It would be silly to "need Oculus" for a Facebook game. Wouldn't that be a turning point in gaming.. requiring Facebook hardware before you can enter a building in a VR world. I guess that's where it's headed, and would be very sad to have that fragmentation in VR.
It wouldn't surprise me if that is how it starts, before consolidating and becoming a more homogenous industry down the road. I agree, it would be sad. I can imagine the majority of people on HN would probably prefer open and less locked in alternatives.