I always get laughed at when voicing this, but I was one of the (admittedly ridiculous-looking) people who tried out the Google Glass when it came out. It was, in many ways, a bad product, but if you could abstract away from how goofy it looked or how bad the battery life was, it was kinda awesome. I tried hard for a couple weeks to use it exclusively, and granted that back then my phone wasn't as much an appendage as it is now, but I found the experience of going back to my phone deeply disappointing. It made me aware, in a way I thought impossible, of just how much I strain my neck all day long to look at the phone, for instance. Calling my wife on Hangout and having her see what I'm seeing and picking groceries together while she was at work was a very neat experience... to have map overlay as I drove on my glasses, too, was awesome.

That's all to say, I think anyone who implements a pretty good version of this with modern tech will usher in glasses as the new compute form factor. Which, paradoxically, is why I think Apple may be the last to do this. Good AR tech will absolutely destroy the iPhone... either they'll do it when they think they are ABSOLUTELY CONVINCED they can successfully cannibalize their own product, OR somehow the iPhone proves to start becoming an unsuccessful business on its own right. I think those two things are pretty unlikely; far likelier for META to keep their nose to the grindstone and perhaps, just perhaps, knock something out of the park.