Well, we're talking about mass market adoption. If they make 1% of people feel sick, that's tens if not hundreds of millions of people who will be actively campaigning against your product. This is definitely into early adopter territory.
Then you need super high graphical fidelity (resolution, refresh rate, field of view, etc.) and super portable equipment.
The current VR devices aren't the first commercially available ones. My first VR experience was in the late 80's and I think it was driven by an Amiga. Thirty years has passed since then and I think that maybe the market is what it's going to be.
AR has a ton of potential though (e.g. windshield HUDs).
Then you need super high graphical fidelity (resolution, refresh rate, field of view, etc.) and super portable equipment.