People don't wear those all day. A scenario where people have cameras on their face all day yields a totally different kind of ability to capture serendipitious moments, etc. That's not to say this value proposition is high enough to warrant it, or that we should expect this technology to actually succeed mass adoption, but it is not the same value proposition as what you're talking about.
Does it? What about gopros or similar action cams, being used for over a decade, and for less than a tenth of the price?