We weren't meant to experience the internet through rectangles.
You are reading this on a rectangle of some sort– a phone, an iPad, a computer. There is likely another rectangle in your hand, pocket, or bag at any given time. One on your desk. One hanging on your wall. We are surrounded by screens, and increasingly we spend more and more time concerned with what is inside them.
In the future, when we all wear computer glasses, we will be inside a screen– one that is the same size as and overlaid on top of our entire field of vision.
Among the gazillion ripple effects that a true AR future will bring is the fact that there will be no need for standalone devices like phones, computers, and TVs.
If you enjoy those form factors, those beloved rectangles can be simulated inside an AR interface. But it is more likely that we will break out of those paradigms and have UI elements scattered all over, however we'd like, and differently in different contexts.
If you are sitting down to do some work, you might want a lot of your field of vision to be covered in simulated screens, like the ultimate multi-display setup.
If you are on the go, it might make sense just to see the little bits of information that you need right now, floating in the air in front of you or projected in the sky.
If you are settling in for some Netflix, you may want a movie theater sized screen that you and others can all view together– a shared experience, but each seeing it in your own headset.
But when you turn the movie off, your living room does not have a TV in sight.
What does this mean for device manufactures?
In 2020, in units sold:
~225 million TVs
~81 million iPads
That's a whole lot of raw materials, factory time, waste products, labor, shipping, carbon emissions, and so on. Not to mention the revenue to those companies from those sales. And it will all eventually drop to zero. We just won't need them.
So enjoy those various rectangles while you've got them; soon enough we'll have the one device to rule them all.