Facebook is much more akin to Google than to Apple because Facebook & Google's primary business is the same - advertising.
And if you're an advertising business your primary objective is driving more eyeballs / more users.
Google's first VR solution demonstrates this - they GIVE it away via Cardboard.
Just look at how Facebook approaches the GearVR initiative - I can't imagine they're making much of a licensing premium but it's dramatically increasing their footprint to be the premier VR solution of Samsung phones (1)
Which is where I come back to why bother with the hardware side as a serious business at all?
Even if I argue that the Oculus Rift is just a red herring to push the medium forward on the hardware side I lose the thread because they seem to be playing such hard defense on the hardware side w/the "app" store . . .
Just release FB Social VR already and win the game, stop damaging your brand w/consumers and developers . . .
(1) http://fortune.com/2016/05/11/oculus-samsung-gear-1-million-...