AR isn't really going to become a thing. Not with current technology, anyway. The problem is twofold: There's no way to get enough power to the device to do anything interesting, and there's no way to make things darker. You can only add light, not subtract it. That means your AR interface will be basically unreadable in sunlight.
The power problem is the real killer, though. Oculus is only successful because it's tethered to a high-end rig. When you don't have that, you're basically tethering a mobile phone to your eyes. Not only do mobile phones die within a few hours if you play 3D games on them continuously, but their graphics aren't very impressive.
There's a third problem worth mentioning: When you're using AR, you're making an overlay on the real world. The real world is instant. Your overlay has to be at least 90fps to look seamless. That means you have to recognize a target + render the overlay within 11 milliseconds. That recognition step is a long way from being that performant.
I predict Magic Leap will be shown to be an elaborate ruse, and they were able to raise money mostly by tricking investors with tech demos that can't possibly advance any further. It's easy to make this claim, but the fundamental problems with the technology seem insurmountable on our current tech tree. It's not quite the same thing as being negative toward a new startup -- most startups have a chance of succeeding if they get users. But you can't get users with AR without wishing for new advances in technology that seem beyond startups' capabilities for the moment.