I wouldn’t say that retro FPS games are all that big right now–for example UT4 or the new Quake game just aren’t that popular.
As far as VR goes, it’s staying around, developers are interested in it enough to keep making stuff, and people like it when they use it, the technology is continually improving so a lot of the issues people have will go away. The big deal is going to be designing games that are clever and use the benefits of VR in a way you can’t get in other games (a must-have game). The issue there is that you’re always limited by your room and so a good game is going to figure out how to work around that limitation.