> (surprisingly, Firefox is not attributed this - they also do not support it yet, and they are not doing anything _other_ than awaiting Chrome's work for it!)

The fuck are you talking about? The jxl-rs library Firefox is waiting on is developed by mostly the exact same people who made libjxl which you say sucks so much.

In any case, JXL obviously has mindshare due to the features it has as a format, not the merits of the reference decoder.