The screen being a fixed distance is the issue. The holy grail would be a system that fools your eyes and makes you think that it isn't at a fixed distance- som

The screen being a fixed distance is the issue. The holy grail would be a system that fools your eyes and makes you think that it isn't at a fixed distance- something like eyeball tracking that detects, instantly, what you're focusing on, and adjusts the perceived focal distance based on how far away the cluster of pixels you're looking at is meant to be. This would improve immersion. HDR is trickier than you think because devices like cell phones can improve their dynamic range by just making the screens brighter- increasing the range by raising the top end- but there's a certain cutoff on how bright a VR screen can be and still be comfortable.