That is only one component of what can cause nausea or headaches within a VR experience. Please see my reply further down for more detail
That said, being on a boat for hours is hardly something we were evolutionarily designed for either, yet no one writes scare mongering articles and posts about that. So you might be doing a disservice with all this worry you're stirring up.
And again, motion sickness is by far the least of your worries. My point was "don't just assume nausea is motion sickness". There are other defects that can cause nausea that are not adaptable.
I think you're wrong about that. Any proof?