The biggest sin was not citing the study. It appears to come from an interview with a professor, and the range is based on variation across applications.
I only got a VR setup this year. I find I am quite susceptible to the motion sickness issues. However, if the game has a good comfort rating and options, I don't have any problems. For example, I need "instant snap" for turning with the control stick and "teleport" or "blink" for movement.
Those options work well for some kinds of games but I will probably never play ones where you need to "move" smoothly without actually moving. Perhaps that is preventing me from adapting to it, but I still say "no thanks" to motion sickness.