Of course, we have to go off of what Oculus and FB says, but they are working to create an ecosystem and market for VR experiences and seem to be pushing VR forward wherever they can; look at Oculus Studio and the work they're doing to create interactive movies, as well as the software deals with partners like Samsung's Gear VR. Plus, VR is one of the three stated future pillars of FB (the other two are AI and Internet-for-all).
I'd be willing to put money on Oculus being around and still being a viable business for FB in three years, even if the Oculus Rift hardware is not a commercial success. If the hardware is not popular, they will still be pushing VR forward in other ways. VR is a huge opportunity and is likely to be the entertainment medium of the future. I sincerely doubt FB is going to be overreacting and shutting down Oculus the way you describe.