Isn’t it just a limitation of human vision? No matter how much resolution we can create, the human eye will only ever see a certain level of resolution … anything beyond that is imperceptible to us. I think I remember reading that 4K is the maximum we can realistically appreciate and anything beyond that is impractical because no one would ever notice the difference.

The only way higher resolutions work is if you start blowing up the size of the image itself. A 20" wide image at 720p looks good but the same image blow up to 60" becomes noticeably pixelated. A 20" wide image at 8K looks sharp and blown up to 60", it still looks sharp.