I don't see that lithography is the barrier to practicality here. IMO trying to make AR or VR happen without some kind of direct link to the visual cortex is like trying to build an iPhone before multitouch capacitive touchscreens were practical.

Smartphones went from "Pointless waste of time" to "Inevitable and incomprehensibly-important technology" overnight when that happened. Jobs had the sense to understand that, probably as a result of prior misfires with things like the Newton. Cook, well, not so much.