It's getting closer to mainstream affordability as prices for the requisite hardware continue to drop. I don't think anyone realistically thought that the VR tech during the Google Cardboard era was going to define the category.
There are now some high-end gaming notebook PCs that have sufficient graphics power to drive VR headsets at 90 fps. The high framerate is key to not getting too queasy.
The headsets themselves are getting cheaper and at some point the battery technology will be enough to drive the HMD screens without adding another two pounds to the headset. Wireless networking is also approaching the point when a computer can reliably send the images over the air rather than through a wire (DisplayPort, HDMI, whatever).
Also, there have been some recent attempts to smooth the VR development environment from the Wild West past and make more of the competing engines and hardware APIs interconnected so content developers worry less about who made what headset.
It's still a nascent category for the Joe Consumer but VR is already here for commercial applications like telemedicine and surgery. My guess is that the military has some interesting implementations of VR technology.