4K is just yet another revision of 2D gaming, and isn't even ultrawide yet. VR is a different experience. If I had to choose between playing pCars2 on my ultrawide 1440p monitor or my low resolution Vive, I'd choose the Vive every time.
Oculus Go isn't really proper VR in my book due to lack of 6dof.
I currently have a PS4 Pro with a PSVR headset and it's such a game changing experience that I've pretty much ignored the idea of 4k gaming since getting it though I'll no doubt upgrade to a 4k TV eventually.
FWIW I bought an Oculus Go about a month ago and returned it a week later as I was simply bored of it and it wasn't anywhere near as good as the Playstation setup. As above the lack of 6DOF head motion tracking spoils the experience and as does just having a single controller since you really need one for each hand else it ruins the immersion.