I don't think its about 4k so much. 4k as a thing isn't that huge. I think this is a reaction to either of two things, one is the existing PS4 is just too rubbish for VR or Sony has found out some key information about NX and is worried their product is not competitive.
To be perfectly honest if the VR headset needs a PS4.5 I'm happy with that. I'll sell my existing ps4 and upgrade to PS4.5 because I'm into VR in a big way.
I'd rather they made the VR headset PS4.5 only than rubbish and also PS4 compatible. It seems like they may throw a few VR scraps to the existing PS4 userbase but it really needs the PS4.5 for the full experience.
Maybe the new PS4 will actually be the PS4 VR console able to run all existing ps4 games as well as VR and 4k games. I'm happy with that.
Maybe the VR headset will also launch with a ps4 exchange program?
If this is a response to Nintendo NX then perhaps we ought to get more excited and finally Nintendo are back into releasing hardware with competitive specs and not last generation performance at inflated prices.
I personally don't think they should enhance 1080p games on ps4.5 I think they should be identical for both consoles that way people with existing ps4's who aren't into VR aren't missing out at all and this will still make the standard ps4 a good choice for those without VR or 4k.
Lets not forget that if the ps4 wasn't upgraded for VR then developers would be constantly fighting the hardware trying to achieve good performance on the standard ps4. To get smooth response and a high refresh rate the games may not even have met 360/ps3 quality visuals we could have been looking at something on original xbox/ps2 quality for the best experience or ps3/xbox 360 level with compromises to quality/performance. At least this way hopefully we will get a far superior experience to get much closer to the high end pc experience.
I don't think it will fragment the userbase as long as sony clearly seperate the vr/4k experience to the ps4.5 and both ps4's get the same standard 1080p game experience without enhancing on ps4.5.
