No other major company has seriously taken the helm on it (at least publicly) and alternative projects, even the most popular ones, seem to lack the vision (pun intended) or seem not to have drawn the lessons from previous tries.
So that's it for this specific piece of hardware. But thinking of smart glasses as just another segment of "wearables" is missing the point. iOS, Android and Blackberry distinct trajectories have taught us hardware can only be as good as the services they support and deliver. "Wearables" are a mean, not an end, and thinking of these 1/ as a product category and 2/ from the specs and features standpoint, would totally miss the bigger picture.
Digital is increasingly becoming similar to electricity: ubiquitous and pervasive. With the objects, digital is expanding from virtual to reality. Here I am talking about our thermostats, black car services, parking lots, products on supermarkets shelves, streets - these very tangible objects actively hold or are passively linked to valuable and actionable data. In that sense, I would rather see smart glasses as interfaces to leverage augmented reality rather than as devices mimicking what smartphones do already (pics, chat, ...).
By pushing the reasoning further, given the amount of objects and yet-to-be-tapped data laying inside them, A/R is one the biggest opportunity ahead, due to grow along with Internet of Things. Way bigger than virtual reality which is itself often underestimated, but has a huge advantage: it has an immediate, crystal clear use case with gaming.
Still, even though massive A/R use cases, justifying continuous use, are yet to be designed, this "interface" positioning seems more solid and more promising than smart glasses being seen as another class of point-and-shoot devices. We may first see vertical use cases, allowing tight design/purpose fit, before moving to mainstream areas. Tech novelist Daniel Suarez did a great work at articulating what integrated A/R may look like in his books (Daemon, Freedom™) - although in a very dark and dramatic setting, but that's what novelists do!
A/R is such a brave new world of opportunities that tech giants cannot afford to miss this. It has the potential to (and - mark my words - eventually will) become a mass market hit. Apple cannot pass on moving devices by the hundreds of millions. Google cannot pass on an interface towards the representation of digital in the real world (hint: think about the billboards, and that's just a very primitive example). Amazon, Samsung, Facebook - they will all have to have a stab at it.
Concepts reboots lead to fresher, bolder thinking, to the benefit of everyone. Before the iPad and Chromecast came along, there were the Newton and Google TV.
So let's look beyond Glass, and ask ourselves: what will be the "Pebble moment" for A/R? What angle will the Ive and Fadell of this world take for the next iteration? Will smartglasses actually take off? Or will human implants come first?
Future will tell.