Why HEIF is not supported by vast majority of computer?I remember those heady five years from 1987 to 1992 very well and still make the occasional GIF despite the 256 colour palette.Remeber when there was GIF but not JPEG?I suspect it's because a lot of software is incompatible with the format while JPEG is compatible with everything.HEIF image is excellent in image quality (4:4:2 10 bit) and compact file size. Nowadays, most of the smartphone and Mac does support it. More TV, computer monitor do support 10bit HDR.
Why some camera manufacturers still haven't implement it?
The trouble with HEIF is that the majority of laptops and desktops don't support it. You can't even upload HEIF to dpreview forums. I lost interest in the format when I tried looking at an HEIF only to find out that I would have to pay for a codec to do so. It may be a standard for macOS (on ⅐th of all laptops and desktops) but it's not standard on any version of Windows (nearly ¾ of all laptops and desktops). Sharing HEIFs is like sharing .pages files instead of .doc or PDF files; it doesn't work for the vast majority of computer users.
It's 2024. Now photography technology is about ProRes raw, 120FPS, H265, real time LUT, global shutter, AI subject detection, why the whole world still uses 8 bit Jpeg?