Disagree on your first point. AI will generate code that is mostly correct, the human time cost of (properly) reviewig this code and correcting it is generally less than also writing it. People that do more serious work than vibe-coding oneshot skateboard simulators in html do actually get noticeable productivity boosts even when every generated line of code is reviewed by multiple people.
That is why the kernel allows it, because they mostly care that a human is around that will take responsability for it, that the patches are of the same quality than always and that everything is manageable by humans. This is in contrast to the techbro github repo with commits that span 20 files and 2k edits where there is no hope in hell to understand what is going on.