What percentage of the population wears glasses now? If you believe the 150 million (1) number, than less than half the population.
How many people can you convince to wear glasses that do not normally?
What about sun glasses? Will I need two pair of Googgles (2)? One for day, one for night?
Do you really think young women (or men) are going to wear these things?
My bet is that this project goes no where with Google in its current form. If anyone has a chance, it's Apple. Apple is the only large company with enough style to make something like this cool/socially acceptable.
If you can make the Camera etc, invisible, then that's a whole different story.
1) http://www.aao.org/newsroom/press_kit/upload/Eye-Health-Stat...
2) my term