Are we talking about 1/3 of the population is susceptibile to motion sickness in general, or specifically VR motion sickness? Because those are 2 different things and I doubt a significant number of the population was trialed with modern VR in order to get a such a clear cut result.

My Quest 2 doesn't give me motion sickness at all but I am susceptible to motion sickness when someone is driving/flying or on a boat. Still, two very distinct things that make a very different statistic.