You're proposing a new way that we could treat authorship that's different from how we currently treat authorship. There's an argument to be had about whether that would be better than our current system. My vote would be no, but I'm not claiming it's obvious one way or the other.
But regardless of whether you think your new system would be better, it's not the current system. Surely the question of whether someone is lying by putting their name on a book they didn't write can't depend on some hypothetical future change to the meaning of authorship that hasn't happened yet.
What do you mean "the" or "our" current system? That's entirely your interpretation, and we've always had a sliding scale of "non-authorship" from editors to ghostwriters. AI models are the same; you can use them in a heavily directed way (basically, as an editor, or in an outsourcing capacity for e.g. illustrations), or in a hands off way that you just endorse.
But regardless of whether you think your new system would be better, it's not the current system. Surely the question of whether someone is lying by putting their name on a book they didn't write can't depend on some hypothetical future change to the meaning of authorship that hasn't happened yet.