Chroma subsampling isn't going anywhere. You'll usually get subjectively better quality with 4:2:0 chroma compared to 4:4:4 at the same bitrate. And this means you can't have everything in RGB, so all the colorspace conversion complexity can't be ignored.
Try experimenting with chroma subsampling in JPGs, but note that not all image viewers have good chroma upscaling. MPV can display still images as well as video and you can choose the chroma scaling algorithm.
Try experimenting with chroma subsampling in JPGs, but note that not all image viewers have good chroma upscaling. MPV can display still images as well as video and you can choose the chroma scaling algorithm.