I know many people who can't play first-person games because of simulator sickness. That didn't stop the game industry.

To add to this, motion sickness from FPS-on-a-screen is inherently unfixable due to the lack-of-locomotion issue. But roomscale VR deals with that issue. VR done right could very well expand the FPS market.

Everyone? It's always going to be a niche thing. There's lots of people who can't play regular video games because of motion sickness, but the video game industry doesn't suffer.

you should replace 'always' with 'foreseeable future'. its plain wrong otherwise.