>Doubly so when you consider that most encoders default to 4:2:0
I agree, but I want to add that this has another side effect you don't mention: it makes high quality images impossible. In 2019, it would nice to have something better than cjpeg -q 98 for near lossless (or completely lossless images). I've spent many hours tinkering with the new inter frame based image codecs, and I haven't been able to achieve this because despite their advertised support for better standards, the decoders seem to have only implemented 8 bit 4:2:0 subsampled sRGB images.
I guess I'll go on storing my photography in 150 MB TIFF files...
I agree, but I want to add that this has another side effect you don't mention: it makes high quality images impossible. In 2019, it would nice to have something better than cjpeg -q 98 for near lossless (or completely lossless images). I've spent many hours tinkering with the new inter frame based image codecs, and I haven't been able to achieve this because despite their advertised support for better standards, the decoders seem to have only implemented 8 bit 4:2:0 subsampled sRGB images.
I guess I'll go on storing my photography in 150 MB TIFF files...