A "hook" is a pretty pure example of musicianship, because it has to be "hooky".
Gregory Bateson said that "information is the difference that makes a difference".
For a musician as for music fans, hooks are like this: a thing will stop being hooky when everyone uses it.
It just becomes part of music language. Indeed you could argue that many of the fundamental qualities of popular music are hooky qualities pushed down a layer or two.
Carly Rae Jepsen's "Call Me Maybe" is an example of this. It's full of very obvious, well-understood musical tricks -- syncopation, breakdowns, subtle pacing changes.
But it's also full of maddeningly effective hooks that are incredibly, even deviously well-crafted. People write songs like this to feel proud of writing songs that get into everyone's heads, but also because it gets into their heads.
Since generative tools don't know how to focus on craft -- or even of its existence -- a good hook is something a generative algorithm will always struggle with, because it requires innovation, and because it is a complex, fragile element in itself.
The rest of it, as you say... it's likely quicker for an experienced musician to just do the work rather than keep poking a generative tool until it is right.
I bet you all of this holds true -- innovation, craft -- even to some extent in quite banal legal filings.
> but there is already a significant amount of automation for the mechanical parts.
Right -- and there can be ordinary, boring, individual scrutiny of what those pieces do, and data/code fixes for them.
I mean, it's no small amount of irony that the systems lawyers use are close to the kinds of "expert systems" that dominated AI development after the first AI winter.
A lot of the rest of the process is actually pretty easy to do without AI for competent arrangers and producers.