Yeah but I think you're unfairly blaming Arch for not being ready for a new GPU on release day, especially when there are still known issues with the upstream packages that are required for it.

I think you may also misunderstand what Arch is. It isn't meant to be absolute bleeding edge. It's meant to be a distro that's as up-to-date as possible yet stable enough for everyday use. So the Arch team does curate upgrades and does QA before they release it to the stable repos.