Depends on whether people actually saw an automobile before they heard about the concept. And of course, people aren't visionaries. They usually do want what they have now--only better. The difference, at least with Google Glass, is that people have seen it and still don't want it. The burden is on Google to show people why they should want Glass. So far they haven't done it.

To be fair, even lots of tech geeks don't want Glass. Overall I'd say it's pretty unimpressive. I'd certainly be interested in a more powerful device of that nature, but Glass seems like a pretty niche product that most people have no use for.