The OP (and the author of TFA) need to think longer-term.
Whether GG succeeds or not in its first incarnation is a completely different issue than whether it will succeed in the end.
The future is here, boys and girls. Humans have been steadily integrating more and more technology into our bodies ever since . . . well, ever since we've had bodies and technology.
Glasses, hearing aids, artificial limbs, portable writing implements, carriable cameras, backpacks . . . the amount of wearable technology is staggering. So we know people will wear technology, and will integrate it into their bodies.
Do people want to take pictures? Yes. They want to take pictures. All the time. Everywhere. Every form factor that you can use to capture an image, people use. People carry around big DSLRs. Compact cameras. Cell phones. And when Google Glass gets to be easy-enough, and cheap-enough, and common-enough, they'll do that, too.
Face it. We are well on our way to recording every freaking minute of our lives, from every possible angle. And Google will store it and search it for us. The only real question left is, will we be the subject or the object of our future? Will the govt and the corps be the only ones who record and use the moments of our lives, or will we as well?
Take back the future. The ability for people to be able to invisibly record anything and everything will also let us watch the cops and the crooks. That's a good thing.
And earpieces and Segway? Actually, more people don't use earpieces because it doesn't work well enough. Yet. When I can stick something in my ear that's near invisible, picks up my whisper, blocks out the ambient noise, and doesn't need recharging all the time, why would I ever take it off?
And look how long it took for bikes to become ubiquitous. Give Segway a chance. Pretty soon you'll see SegShare along BikeShare.