The tech industry has spent roughly a gazillion dollars trying to convince people to strap face computers on their heads. It hasn't worked.

But the tech guys haven't given up. Their new pitch: Instead of buying bulky goggles that replace your reality with a computer-generated version of something else, what about some glasses?

At first glance, this makes a bunch of sense: People don't wear big heavy stuff on their head unless they have to — like if they're skiing, perhaps. But lots of people wear glasses. So if the tech guys want to sell new tech, they should stop trying to make things people don't wear and focus on the things people already wear.