It's not 80% because there isn't a definite price on it. The $1500 is like a developer kit. Honestly, I can't fathom people paying $1500.00 for this. If it costs that much, even half that much, I really think they will struggle to sell very many units. $300 is a sweet spot.
I'm interested in what this could offer me. I'd like to have it as a smart device maybe that could benefit me fitness wise and music wise. I doubt the bone conductor will be a good music device, but in a pinch, it might work. Maybe I could replace my contacts with prescription GLASSes, probably not, how bout sunglasses, Yeah that'd be cool. 300 Dollars would be a good price IMHO, It's pretty well "crafted" and would pair great with my Nexus 4.
official google glass price has never been mentioned. the $1500 price was just for the people who really REALLY wanted in on the beta testing. $300 or lower is a very believable price for such a product. of course this price would be without any specialized glass.
This device will have a pre-release in about 2 months or so. Cost will still be about $1,000 since it has no competitors on the market (I'm sorry, I don't consider the Jet to be a real competitor). I've tried this device myself with people that work on site, WITH web browser functionality.
Let's not also forget that common cutting edge smartphones are actually more like $500-$700, and only cost us $200-$300 because they're subsidized over the life of a contract. I predict a $700 price for general release with $1k for pre-release.
I'd like to add that I personally emailed Tomshardware about a week ago with a huge paragraph of information on this device from an insiders perspective. As usual, they are too slow and still haven't responded.