Today, Sony officially launches its PlayStation VR headset. It’s this year’s last real hope for turning a serious VR device into a commercial winner and proving that there is mainstream demand for the technology—something that even the leading lights of the field admit hasn’t yet happened.

The new rig certainly shows promise, with the potential to beat competing devices such as the Oculus Rift and HTC Vive. For one thing, it’s cheaper: at $399 it compares favorably to the other two devices, which retail at $599 and $799 respectively. It’s also powered by Sony’s PlayStation console, which many people already own and is cheaper than the powerful PCs required by the other two.

It clearly has a market advantage. But that assumes that there’s a market ready to exploit.

Despite 2016 being billed as a banner year for virtual reality, people aren’t yet buying fully fledged VR headsets at the rates that Sony, HTC, and Oculus would like. As New Scientist points out, devices at the lower end of the sector, such as Google’s Cardboard and Samsung’s Gear VR, appear to be slowly gaining traction. But more powerful devices are yet to sell at volume.

Mark Zuckerberg admitted as much at the recent Oculus developer conference in San Jose. There, he said that the Oculus Rift had suffered from a “slow start.” That echoes earlier warnings from the Facebook CEO, who has suggested that VR could take as many as 10 years to hit the mainstream. “These kind of new platforms take a long time to develop,” he pointed out in a recent earnings call.

Those sound more like explanations and excuses than solutions, though. John Carmack, the chief technology officer at Oculus, thinks he’s identified a major problem with the technology. Here he is speaking to Business Insider:

"We are coasting on novelty, and the initial wonder of being something people have never seen before. But we need to start judging ourselves. Not on a curve, but in an absolute sense. Can you do something in VR that has the same value, or more value, than what these other [non-VR] things have done?"

That is a very good question indeed. It’s perhaps no surprise that, currently, watching movies is one of the go-to VR activities—because other than that and gaming, just about anything else can be done just as efficiently on a PC or tablet. Mark Zuckerberg promises that VR will be a next-generation computing platform, of the magnitude of PCs and smartphones before it. But, as Carmack says, first it needs to find some more compelling use cases that people find valuable. Until that happens, sales are likely to remain slow.

(Read more: Reuters, New Scientist, “Why Oculus and HTC Need to Watch Out for Sony in VR,” “Facebook Begins Its Push to Make Us Socialize in Virtual Reality,” “VR’s Big Surprise: 3-D Worlds Have Little Appeal”)