I couldn't see this being farther from the truth. If it was a useful product in its current incarnation then people would be using it. I think the real problem is as of right now it just isn't that useful.
Wearable technology will come into vogue the same way - you can't make something fashionable just by making it unobtrusive or inoffensive, it will be considered fashionable when the celebrities who set trends find it useful enough to start wearing it. And no google, paying models to wear it during fashion week doesn't count.
For instance, I would not mind an overlay 'head up display' on a cycle commute with cadence, an idea if I was on time relative to my normal journey and generally better 'telemetry' than available with the glorified digital watches that pass for cycle computers. If I could also use Glass to communicate with other riders on the road then I would be able to find more uses, e.g. if cycling with a friend and not wanting to shout whilst riding two abreast. Just having decent eyewear - the part an Oakley could bring to the table - might be the reason I would wear the things.
The rise of Oakley - starting way back in the 80's when their cycling goggles looked like ski glasses - is something I think the Google Glass team can learn from.