@gabriel
You can thank Google for that, they go great lengths pushing WebP and hindering JPEG XL's adoption: https://www.theregister.com/2022/10/31/jpeg_xl_axed_chrome/
As most modern browsers are based on Chromium and Blink, the outcome of it is obvious.
They also seem to have great influence over Mozilla, as they have made support for WebP not optional like it was before: https://breloma.m0xee.net/notice/AclXgvk5sDRNX7rr5E
I quite literally had to patch the option to turn it off back in.