Look at the success of wireless earbuds, they will be part of distributed wearable AR systems, they're screenless AR that exist already. AR doesn't always mean screens. Glasses can replace screens, but they won't be worn by everybody like Phones, so AR glasses will first compete with desktop, laptop and tablet screens in more professional environments. It can only go mainstream like phones in contact lens form, or some kind of iris projector that sits on your nose, likely still powered by a watch or a phone. Not sure if we see that in the next decade though.