Hmm i mean we are talking pixel counts higher than 1080p with all these headsets, so its hard to believe that any connection other than HDMI/DP direct to a good GPU is going to give monitor equivalent quality?
How do these visuals compare to looking at a sharp monitor image?
I watched a youtube video of assetto corsa and the guy was talking about how far away he could read the brake distance marker numbers on the track. With a monitor he could see them from hundreds of meters away and with a headset (can't recall which one), it was about 100m. However what i thought was, well how well could i see the distance markers when driving a real car in real life with my contact lenses in! Because the whole point of VR is realism and my eyes aren't pin sharp at hundreds of metres away in real life.
Rift and Index are direct connections to the PC so they will have a better image. The Quest is completely different its a standalone headset based on an Android device so doesnt need a PC. Where the PC does come in though it uses desktop software to "stream" the video/audio/controls to the Quest via WIFI (Virtual Desktop) or USB-C cable (Oculus Link) so think Google Stadia or any of the game streaming services you read about. The picture quality is not quite as good and depends on your WIFI being good. Obviously with a cable doesnt matter.
This will give you an idea this is the Quest Virtual Desktop v Oculus Link