How is this relevant to this article given that Firefox has never shipped JPEG XL support in a public build? Not even behind an experimental flag like Chrome did.
It is possible that FF won't continue the work of implementing it if they see no future without the oligarch in the field, but we'll see
All browser vendors are pretty reluctant to add new codecs, because there's always going to be yet another promising codec to add, but they're left maintaining all of them forever, even after they're not cool and new any more.
8-bits per channel and YUV420 only were caused by hurrying it.
With JPEG XL we have the opposing mistake. We had a great format already in 2017, and spent 5 years more for improving it further.