Or the opposite, when glasses can have built in 1440p "augmented reality" oleds, each viewer can have as big of a display, with black pixels, as they want.
Basically, any system that requires your eyes to focus on a physical screen that isn't the same distance as virtual objects will piss off your brain, because it knows something is going on, and hates being tricked without consent. Some people I think can ignore this effect to some extent, others cannot. It also strains your eyes more than focusing on an actual 2D screen so increases eye fatigue compared.