> It is an obvious idea. AR/VR is hard. Dumb displays are not. I think we should have had similar products a decade ago, and if I'm not mistaken, these exist in cheaper SD versions from noname manufacturers.

These products have existed for decades. I can't find the one I remember seeing ads for during the 2000s, but Sony had one in 2011 called the HMZ-T1, they had a much earlier model called the Visortron. I think the widely advertised ones were maybe iTV goggles, but I can't find any history on them. Typically advertised as equivelent to a large screen tv farther away.

If you want a demo of a real product, call around to children's dental offices. Many of them have (or have had) these to help distract kids during exams and procedures, although mounting a tv above the exam chair is also popular (a lot easier with a lightweight lcd or oled than a crt or plasma)