Google has resumed work on JPEG XL support in Chromium after removing it three years ago. A developer says the current version is feature complete and under review.
My impression is that for ordinary non-power users it was supported from the start (i.e. the commonplace image viewers and editors could open it - at least I personally had no issues), it just felt annoying at first because it seemed forced upon the user.
So it’s basically “nobody wants to use it because nobody is using it.”
I actually rather like it, and at this point many of the tools I use have caught up so I don’t mind it any more myself.
My impression is that for ordinary non-power users it was supported from the start (i.e. the commonplace image viewers and editors could open it - at least I personally had no issues), it just felt annoying at first because it seemed forced upon the user.