Google Glass was totally invisible at I/O 2014.

Two years ago, Google co-founder Sergey Brin had a friend put on Glass and stream his dive from a plane to the top of San Francisco's Moscone Center. The mood was one of excitement and almost awe — few people had even seen Glass in person at that point, let alone used it. Things were quieter at the I/O 2013 keynote, but workshops later in the week taught developers how to work with their headsets, which had started arriving just a month earlier. "There's a real opportunity for Glass to become mainstream," said product director Steve Lee in a fireside chat.

Google has been nothing but positive about the beta program

There are still Glass events on the schedule for I/O 2014. At the keynote, however, there was no mention of it, nor was anyone wearing a set on stage. For plenty of the company's experimental products, this wouldn't be an issue. No one expects Google to give us self-driving car news at a developer event. But Glass isn't a new device that people are just starting to figure out, it's a $1,500 product that's been in beta for over a year. After being distributed through a slowly growing "Explorers" program over the course of 2013 and early 2014, Glass sales were officially opened to the public last month. Google called the response to an earlier, temporary sale "overwhelming," and it's been nothing but positive about the project. At the I/O keynote, it had a chance to shore up support among developers and techies who won't join the beta but still want to see Glass succeed.

Which makes it all the more frustrating that Google has remained so quiet about turning Glass into more than an experiment.

To be sure, we've seen progress on the beta front. Glass' original futuristic wireframe has been joined by a line of fairly ordinary prescription frames, and it recently signed a deal with the company behind Ray-Ban and Oakley. It's announced a certification program for business apps and expanded Explorer sales to the UK. Most recently, it introduced a modified version with double the RAM and an expanded battery, promising faster performance and a 15 percent longer life between charges. But a consumer release, or even a firm date for one, is perpetually just over the horizon. At one point, Google hoped it could sell a cheaper final version in 2013; that date later slipped to early 2014 and is currently closer to the end of this year, with no indication it won't be pushed again.

Even with prescription frames, Glass is clunky

The obvious reason for this is that the technology still just isn't there for Glass. Battery life has been one of the biggest limitations, and even with improvements, it's a difficult and particularly important question. If you want people to replace their regular glasses with augmented reality ones, they'd better not go dead before the end of the day. Even with prescription frames, Glass is obvious and a little clunky. It's impressive engineering, but practically speaking, you can't do things you'd take for granted with a pair of ordinary glasses, like fold them up.

Perhaps the more important question is how much it's going to cost. Early adopters have been willing to pay $1,500 for a beta version, but that's an astronomical number for the average electronics buyer. Google has said it will get the price down, but even slashed in half, it's more than the off-contract price of your average smartphone. It's not that Google can't come up with a way to make people buy Glass. It's that it's given virtually no indication of how it might do so, at least for consumers — surgeonspolice, and other professionals are a more likely target.

A year later, Glass remains something 'Those People' use

Google's Explorer program successfully got Glass into the hands of developers and celebrities, but this may have primed everybody else to hate it. Privacy concerns have led some bars and restaurants to ban Glass, and legislators are weighing how to integrate it into distracted driving laws. Google has urged Explorers to help burnish Glass' somewhat tarnished reputation by giving them a list of etiquette guidelines, striking back against the "Glasshole" label bestowed upon obnoxious users. The original concept video did a great job of selling Glass' possibilities, but software limitations and a focus on social media instead of augmented reality made the early results a disappointment.

There are growing pains with any piece of technology. The now-ubiquitous iPhone seemed strange when it first came out, and it arguably still poses more worrying privacy concerns, but its success forced us to develop social norms around it. The combination of price and exclusivity, though, has left Glass a device that Those People own, not your classmate or coworker or family member. A year out, most people can't play around with a set, figure out how it works, and think about investing in their own. And at its biggest event of the year, Google spent more time on cardboard virtual reality goggles than it did explaining how it proposed to set things straight.