It's called, “getting your VR legs”, akin to sea legs. It worked for me, at least. As an extreme example, I can now play as a character in a space suit, twirling and spinning around for hours, without getting motion sickness. I also regularly play rally racing games where I'm constantly subjected to bumps and jumps, and don't notice it at all. This was after around 100 hours of VR, I think.
Actually I've found the experience somewhat magical, in that I get the same stress relief from being couped up all day by leaving the house to go do something outside as just playing a game for an hour or two. It feels like I'm actually going to another place, nowadays.
This really only started when I got the high end, Valve Index, which has a 90hz+ refresh rate, so maybe that has something to do with it.
IPD alignment is adjustable on most headsets nowadays. My experience is anecdotal anyway and I fully accept that some people can't handle it.
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.
IPD adjustment knobs are there, getting it correctly calibrated for your eyes is still not easy. It takes either a direct messiness with a ruler or a 5-10 minute calibration process in-headset.
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.
Actually I've found the experience somewhat magical, in that I get the same stress relief from being couped up all day by leaving the house to go do something outside as just playing a game for an hour or two. It feels like I'm actually going to another place, nowadays.
This really only started when I got the high end, Valve Index, which has a 90hz+ refresh rate, so maybe that has something to do with it.