I believe this will be a bigger problem than a fair few realise.
The only time I've personally experienced motion sickness in a game was using Kinect as a head tracking device in Forza, sadly something I'd been pining for. Main reason being was the relatively high latency, something OR still has from my understanding. There's a large chunk of people who cannot play first person perspective games due to motion sickness, I'd imagine it will only be amplified by virtual reality devices. That's going to be a lot of people excluded off the bat, I've also read of developers only being able to use the OR in 20 minute sessions before the sickness became unbearable. Home users will be expecting far longer sessions, if large numbers cannot do this then I would hazard a guess at the whole shebang being a hard sell.
It's going to be an interesting in some years from now, I wouldn't be surprised if augmented reality takes off beforehand. Being able to see what is around the wearer is going to help a lot, not to mention allow for many more situational uses. For example, people with kids cannot use a completely sealed environment like OR and closed headphones, but glasses which project a screen image and an ear bud will be workable. For me it depends on how rapidly all these technologies move forward, could well still be something of a flash in the pan. I know the following is usually dismissed out of hand but I recall much of the same being said in the early 90s, big documentaries and news outlets running with how it will change medicine, learning, entertainment and all the rest but that never transpired. Yes, things are a bit different now but has it all changed enough?
We'll have fun finding out either way, I'm sure.