I strongly disagree. Yes, nausea is a big problem but there are a lot of scenarios/games where you don't need locomotion or can comfortably work around it (warping, a cockpit of some sorts etc.).

Also we might be closer to solving the eye vs. inner ear discrepancy completely rather sooner than later. Samsung is working on a headset that stimulates your vestibular system to make you sense motion & acceleration: http://www.theverge.com/2016/3/14/11220836/samsung-etrim-4d-...