The rhapsodic crowds at the Consumer Electronics Show. The around-the-block lines at South by Southwest. Most of all, the $2 billion purchase by Facebook. That fall Oculus was still just an ambitious startup chasing virtual reality, a dream that had foiled countless entrepreneurs and technologists for two decades. Oculus’ flagship product, the Rift, was widely seen as the most promising VR device in years, enveloping users in an all-encompassing simulacrum that felt like something out of Snow Crash or Star Trek. But it faced the same problem that had bedeviled would-be pioneers like eMagin, Vuzix, even Nintendo: It made people want to throw up.