Re: 4k vs VR
"is 4k going become a poorer relation to VR gaming?"
Not a chance. VR is only good for a limited selection of genres; if it's not in first person then VR is at best pointless and in many cases is actively bad. Strategy games, platformers, pretty much anything in third person, most casual things, and especially anything with local multiplayer or that might be enjoyed by more than one person at a time, are all much, much better with a regular screen than any kind of VR setup. VR is essentially like a joystick - it's awesome in the games it's actually appropriate for, but you'd be mad to try to use it exclusively for all games.
As for price, for both VR and 4K the biggest cost is the horsepower required to run it in a way that doesn't make you motion sick or look like a slideshow. Oculus Rift is supposedly going to be around £200, and you can already get a 4K TV for not much more than twice that. Give it a few years and a basic 4K monitor that most non-hardcore gamers are likely to be looking at isn't going to cost any more than a decent VR setup (and of course there will be much more expensive versions of both for those who want them).