Really? Nowadays ive found it hard to get good 4k hdr downloads of things with seeders. Piracy seems to top out at 1080p at least it bittorrent land
FWIW I have 20/10 vision (twice as sharp as "perfect normal") and have never seen the appeal of retina screens or 4k.
edit: Also the file sizes are vastly larger for 4k for an incremental benefit.