No one Ive met can stay in VR for hours regardless of game. Most of my friends who have tried or have VR devices get sick after 45 minutes. Admittedly they are not VR enthusiasts or hard core gamers however.
I'm not saying this qualifies as any sort of degree nor was I saying you should count my anecdotes as facts.
It is simply my belief that the vergence-accommodation conflict needs to be solved before VR will be adopted by the masses. I think vergence-accommodation neurological process should stay coupled as it does in nature to provide a completely natural feeling and non strained experience for the user. The research here is scant. Perhaps someone is aware of some ongoing research on this topic.
EDIT> I have a relatively low tolerance for motion sickness.
I've read that this is a problem for astronauts IRL when they're in free-fall next to a slowly rotating or panning object that occupies a lot of their field of view. So, that would be a kind of existence proof that it's not vergence, but rather optical flow that is decoupled from the subject's actual motion.
It sucks, but basically FPS games are out for VR, until you can actually run around, leap, etc.
EDIT> Another example -- during a scene in Apollo 11 where the camera (and hence my view) was orbiting the spaceraft while my IRL body was still, I started to feel queasy. I was able to reduce the sensation by looking at the growing space-craft as it started to fill more and more of my field of view -- it was relatively stationary to me. This again speaks to optical flow, and motion that is out of whack with what the player's ears are telling them. Another cheat along these lines is to use a cockpit that is fixed relative to the player's view to reduce the amount of visual area that is giving wrong motion cues.
EDIT2> I'd be interested to know whether you can last longer in a game that uses only your own IRL motion + instant teleport. So, no thumbsticks, mouse, keyboard locomotion -- as these are all known chunder inducers. Unfortunately non-VR games with bolt-on VR are like the worst-case for comfort, but also often the games that we really want to see in VR.