Browsers (javascript) are still singlethreaded, VR requires greater graphical fidelity (in regards to framerate in particular) than current gaming platforms are accustomed to generating, and VR requires sufficiently small input lag that cloud gaming is rendered impotent. The best path on the browser is asm.js, but it's still years away from running crysis at acceptable speeds. Decades from running it on an arm cpu.
TBH, my gut is that facebook (will) set VR back by about 5 years thanks to this purchase. The innovation will be a slow burn rather than a magnificent explosion. it is what it is. Helps sony and ms, hurts valve...
If they stayed totally hands off? No shift to OR web services, unyielding focus on cutting edge gaming? Sky would still be the limit. I just can't see facebook going down that path for more than 12 months. IMO the talent (Carmack, etc) will start to bleed away by then.