I don't know, but my guesswork is that the DNG/ProRAW/JXL support comes with compatibility challenges. Limiting the size of the launch to well-informed photography prosumers and professionals will help to iron out the compatibility challenges — rather than make all confused consumers face these challenges at once.
I don't think that hardware support plays a role here. The fastest encoding modes of JPEG XL are ridiculously fast on software, and Apple's CPUs seem powerful enough.
I don't think that hardware support plays a role here. The fastest encoding modes of JPEG XL are ridiculously fast on software, and Apple's CPUs seem powerful enough.