There are a lot of psychological factors that go into tricking the brain into "being present" in the VR space. When you use that $60 VR headset your seeing neat VR technology but your brain is never tricked. There is tons of research on this going back to the 70's. The Vive / Oculus is basically the first time we are getting close at this price point. There is still a ton of hardware and software work needed. For example seeing a fake body in VR takes you out but seeing your hands 100% tracked makes takes you back in.