Virtual reality is the technology that keeps on promising. For the past decade, the promise has seemed so much closer, especially when Oculus came along looking like such a game-changer that even Facebook invested $2 billion on it in 2014. Host Molly Wood spoke with Blake Harris in March, the author of “The History of the Future: Oculus, Facebook, and the Revolution That Swept Virtual Reality.” This is a re-air of that conversation.