I just remembered another one, the Sega Gigadrive! Segas super secret project that would kill nintendo, feed the hungry and solve world peace.
I guess that's why the saturn started off as a good 2d system
The VR problem of headaches/puking can be mostly be solved, the basic problems is pretty much the same as seasickness. Motion not being consistent with what we see and the brain interprets as the actual motion.
That like the flying Car is more of a practical limitation on how much you can spend on hardware and environmental laws.