Yet google glass wasn't popular, partly because of camera-privacy, partly because it couldn't block light, only add it (though Magic Leap has apparently solved this latter problem.)

Tim Cook also pooh-poohed headsup displays as a barrier between people, instead of connecting them. But, since earplugs and people checking their phones already disconnect people, this seems like diversionary bs to me. Apple is surely working on this, as they work on many things.

Small displays are the problem, bigger phones are popular despite their awkwardness. Headsup displays solve both: large display, out of the way.

Not sure about input; gesturing to yourself is going to look even crazier than talking to yourself.