"Sick" is definitely a relative term. I've given literally thousands of demos to people--some of which were pretty janky, back in the early days--and I've yet to see anyone throw up from VR.

There is a very small minority of people who put on the headset and immediately can't stand it. I've seen maybe 2 or 3 people in the last 6 years, so it's definitely less than 1%.

Depending on content, I've seen about 50% of women and 25% of men experience mild discomfort after using the headset for about 30 minutes. Studies on simulator sickness include that in "feeling sick".

My current project is not able to use every single sim-sickness mitigating strategy available, due to the sort of source data we're using (a lot of flat, 360 imagery in a multi-user tour-like scenario), but even there, we've only had 1 out of 100 people express actual feelings of nausea after using the headset. If people report any discomfort at all, it's on their first time, after they've not heeded our warning to limit their first interaction to 30 minutes, and then they only mention feeling a little light headed.

People report feelings of nausea after playing 1st-person shooter video games on large screen monitors or watching shaky action movies at movie theaters. This is not a problem unique to VR.

The study was designed to find factors that correlate with VR sickness, and as such, only studied 83 people, all "highly stressed", and showed shaking videos as their methodology. I think it would be a statistical mistake to generalize from this study.

Anecdotal, but a lot of people seem to be able to get over their VR motion sickness. I personally did by just playing the janky Rocket Mode in Richie's Plank Experience a lot. Same goes for heights in VR, at first it's terrifying but if you repeatedly expose yourself to it it loses its effect. There's also a story of a VR dev who built a demo to get rid of his motion sickness, it involved just repeatedly dropping his POV from a height and then looping back to the top. Granted, some people will probably never get rid of their motion sickness for whatever reason but I think those will be in the small minority.

I got rid of VR motion sickness after a while. Same thing with DOOM back in 1994 or so.

There is a problem though with a lot of crap games not implemented with comfort in mind and badly optimised. Stuttering will get you feel bad fast.

To me it sounds similar to all the reports of motion sickness (or worse effects) from playing Doom back in the day. I also suspect most people who do suffer from it can get used to it over time.

OTOH, considering how many people keep having motion sickness in cars (especially when not driving and reading and whatnot), perhaps for some people the issues remain.