Yes, that is a huge issue. I hope that 240Hz+ refresh rate along with 10K Hz eye tracking will go a long way to alleviating vergence-accommodation conflicts or simulating some of what a lightfield display offers. I don't foresee them being perfect though, but also people are somewhat adaptable. VR displays are mediocre and most of us get over the imperfections and nausea fairly quickly. What long-term issues that could cause with MR use will be interesting to track.