[pyottdes]

I think it's interesting to think about it as a hardware evolution question. If you look at a timeline of what it took to get to the modern smartphone, you could (arguably) say:

PalmPilot -> Handspring -> WindowsCE -> Blackberry -> iPhone -> Android -> Modern Smartphone

Each one of those evolutionary steps brought in a larger user base and grew the feature set of the prior generations hardware. The VR/AR/XR market comes with its own set of challenges so imagining where it maps onto that timeline is hard, but I would guess we are still more in the Handspring - WinCE era of these devices.

Wearable display systems have a solid and growing user base but the hardware is still a ways off from something that will have mass adoption. The roadblock is very much in the hardware, not the software IMO.