This means that Facebook paid $3 billion for Oculus and has made less than $500 million in VR sales.

Sony did put out some sales figures for its Playstation VR headset in February which caused some initial excitement — with the company claiming 915,000 units sold since October 2016. But by June that figure had merely drifted past 1 million.

Famed movie director James Cameron noted the problems two years ago.

"There seems to be a lot of excitement around something that, to me, is a yawn, frankly. The question that always occurred to me is, when is it going to be mature, when is it going to be accepted by the public at large, when are people going to start authoring in VR and what will that be? What will the level of interactivity with the user be other than just 'I can stand and look around.' If you want to move through a virtual reality it's called a video game, it's been around forever. Oculus Rift is fine, it's got a good display and that sort of thing,"