Unlike public companies, Valve can afford to be cautious about VR's potential. In a clear jab at rival Oculus, he pooh-poohs overblown expectations of a mass market any time soon.

"Some people have got attention by going out and saying there'll be millions of [VR unit sales] and we're like, wow, I don't think so. I can't point to a single piece of content that would cause millions of people to justify changing their home computing.

"It's a great thing for enthusiasts and hardcore people. Where we are today is way further down the road than we were a year ago. But it's just going to be this slow, painful fits and starts kind of thing. So while we are really happy with how things are going, yeah, it doesn't match up with what other companies are saying."

The big obstacle is price. A Vive currently costs $800 and requires a high-end PC to work. Despite expectations of first-year price decreases, this does not presently look likely.

"If you took the existing VR systems and made them 80 percent cheaper, that's still not a huge market. There's still not a really incredibly compelling reason for people to spend 20 hours a day in VR.