VR keeps tripping on it's own two feet.

[Weltall]

I think of things like Oculus as not being an attempt to revolutionize immersive virtual interactions all by itself (regardless of any claims that the inventors or backers might make), but as merely the latest, and perhaps biggest, step towards building what you described: full-immersion virtual reality processed entirely within the brain.

As for how long that will take? Who knows. Ray Kurzweil thinks we're no more than 30 years away from the Singularity, so if he's right, we should all live long enough to see it.