[majormajor]

People spend thousands to avoid having to wear glasses or contacts all the time.

Now you can wear them all the time again, but now with more ads?

EDIT to add something less snarky: phones were a "here's another thing to carry in your purse or pocket" additive thing to lifestyles, which wasn't too big a burden, and then gradually got more and more useful. Glasses and contacts, on the other hand, have decades of evidences of people actively avoiding them except for situational stuff. So them getting as pervasive as phones would need a lot more behavioral change.