^ Well, it's just trying to launch a product before the tech is there.
Like the iPhone.
It's not just that, no one had thought about it, it's that the individual parts had not matured to a level where it was possible to combine the elements into a single small device.
You can't make a nice car unless you can make metal, extract plastics from oil, invent electricity blah blah.
For AR we need the display, the computing power, the battery, the rest is almost the easy bit?
As far as I know right now, Apple will do this like they did the watch and offload the power to the iPhone, so that's solved. They just need to get the battery and display into something small enough that people would be happy to wear it.
Contact lens's a lot further off I'd imagine, though I know it's being "Looked into!"
Perhaps it will be like the iPhone. The 1st one comes out, which finally brings it together, but it's not great, however, it's the starting point, and then over the next 10 - 20 years as everyone refines every part of it, we get to a point when it becomes the norm.
by 2050 almost everyone wearing AR device, as if you don't you are missing out on so much?