Apple usually only play to win. VR in general is still very immature. Sure Apple is researching like other companies but I think they won't launch anything until they come up with a really flawless, gorgeous device (then, as usual, it will become the product to beat).
They do not try to "invent" at any cost. They usually just are the first in doing something "well" and then the competence change its previous devices to copy them (sometimes they fail, obviously) . The day Apple launch a VR device will be the day that really usable VR arrives to the world.
I don't expect this to be anytime soon anyway. They seem to be more interested in AR due to its practical applications in real life.
This sucks, because I can't have a proper VR device (I don't want to buy a PC or Android system only for VR). I dream with Apple introducing a "gamer" desktop computer (with its own VR headset?) in the upcoming keynote.

