The Rift uses the power of a PC and the Oculus Go just mobile tech, which isn't powerful enough...
If you viewed a zoomed in portion of a 5K video on a 1080p monitor then you would be able to see the detail of the image.
it's like viewing a 5k picture on a 1080p monitor
Protocol7 said:Similarly with VR video, the 5K image is
spread over a 180 degree (or 360 degree) field of view and your headset
only displays a small portion of that at any one time. You move your head around and it shows you a different slice of the video. For a 180 degree video, 5K is barely adequate to look acceptable. If you watch lower resolution videos you will easily see the lack of detail.