In my opinion Google Glass is set to be a game changer from the start. I wager that when google glass is launched, it will be a cultural icon no more than 1.5 years later.
It's clear WHY google needs glass. Owning the channel between my eyes and the world is a huge potential pot of money. Targeted ads have a lot of potential to disrupt the ad space, and if facebook ever decides to make their own ad network (such as Google's ad sense) competition will be fierce. Google glass is a really good way to increase their competitive advantage, and cement their position in the advertising arena.
Additionally, of the companies that would be interested in making a product like google glass (facebook, microsoft, IBM etc) Google probably has the best mix of engineers to do it. I've always said that Google is an AI company first. Well a huge part of AI is machine vision, and a large part of successfully monetizing google glass is machine vision. Additionally, with street view, and other aggressive initiatives Google is in one of the best positions to actually understand what and where the world you are looking at. Finally, while google has proven in the past they are weak as a hardware company (nexus 1) they have demonstrated they are capable of bringing a consumer product to the mass market... though perhaps maybe not enough to make it anything less then a wild card.
Finally the last point is one of consumer adoption. The newton pad was not successful in part because the hardware was premature. But I would speculate it was also in part because consumers weren't at the point of understanding the value. The hardware in Google glass is unknown at this point, and potentially could under-deliver... and that will cause it to be a newton.. but for the reasons i said above I think Google is capable of delivering a quality product. However consumer readiness will not be an issue. 1 billion people are already on Facebook. Social interaction through technology is accepted today more then ever before. Using smartphones in public is not only accepted, its normal. Years ago using a PDA might have made you look like a yuppie, but today no one would notice.