No. demetris’ benchmark of lossless image compression is not a sign that the situation may be changing. :-D
That was just the context for some reading I did to understand where we are now.
> BTW, I don't see how Mozilla's interest in a jpegxl _decoder_ (your first link) has anything to do with the performance of jpegxl encoders compared to avif's encoders. In case you're really interested in the former, Firefox now has more than intentions, but it's still not at production level: https://bugzilla.mozilla.org/show_bug.cgi?id=1986393
That is one of the links I shared in my comment (along with the bug title in parenthesis). :-)