Yes, JPEG 9 will soon be obsolete and replaced by JPEG 10, as announced in 33 Years JPEG: Ubiquitous Presence and Still in its Infancy.
“JPEG XL” is totally useless, as everything else that came from their side, and it will never be used on the Web: Historical yearly trends in the usage statistics of image file formats for websites.
As you can see, WebP has just overtaken GIF, but nothing will ever overtake JPEG for natural images, because that is the only technology with substance. Your points are simply meaningless and have nothing to do with substance. The substance of JPEG is in four fundamental properties for image representation.
By the way, we released in 1991! It is the pretenders who refer to 1992, and from this case alone you can infer the fake. Everything they do is junk, to date, because it has no substance.
Regarding arithmetic coding, see my recent post here.
Regards
Guido
JPEG developer