The author is missing the _hardest_ part of small hardware: power management.

The reason why AR glasses are not a thing yes is because there isn't a big enough battery to allow them to function for more than a few minutes.

Glasses form factor have space for about .9watt hours now, and ~2 in 4 years time (assuming current trends) Assuming a 14 hour day, that means that your have 140mwhr to spend every hour. A not very bright light on your glasses is about 30mw, a decently bright one is 90mw. Processing imagery on that kind of budget requires custom silicon, and a huge bunch of optimisations.