It's fine we disagree. Let's avoid the trap of right or wrong. Ai is new, and our opinions will evolve over time. With that said...
> "indisputably Hayao; any fan of anime will recognise his style immediately"
No they wouldn't. If you're talking about a still frame, nobody can be certain who the artist is. Why? Because LOTS of artists make similar work. You think there's an indisputable signature in every drawing from every artist? There really isn't.
There may be an obvious signature, such as placing an "upside down umbrella" in every piece they make. But the Ai won't copy the umbrella, because that would be replicating the work rather than style.
There are books about Miyazaki's style, authored by him that go into detail and share everything from concept sketches to the use of computer graphics in his films. It's all there in the books he wrote explaining and SHARING his techniques with the world. But what he can't share, and what can't be replicated with prompts, is the brilliance of the storytelling that threads the vast body of visual work to create the whole.
> unique style
Again, you're claiming an artist's style is unique, when in fact the vast majority of "styles" are blends of other styles and influences. No artist was born in a bubble.
Even if there is a unique visual signature, so what? It's not the heart of the work. It's a preferential technical characteristic.
Not only that, but this world is saturated with images. Even in music, it's difficult to come up with an original riff that doesn't sound like an existing song. The musician, in order to be awarded "originality", needs to use the full 3 minutes of the song to involve lyrics and other elements before something truly "unique" emerges.
You think there's an infinite bucket of "styles" visual artists can tap into? There isn't.
Content choices and narrative choices are more important anyway. For example, the artist may have something to say about humans being cogs in the machine. Sounds interesting. Such concepts form part of the style and reputation of the artist. People follow artists largely because of their artistic substance.
You're too focused on visual technique. The guts of any good artwork is the whole package, including the symbolism and balance of meaning in the work.
What is the artist SAYING with the work. Ai won't help prompters with quality of symbolic meaning, concepts and interlinking symbolism, subtext, balance of imagery, subtle visual tension... all the things that make ART ART -- the ESSENCE of art is found in the body of work.
So... Ai can generate a sci-fi robot running through the city, and your concern is this impedes the profit margin of real artists pumping out the same generic stuff? Sorry, but I won't shed a tear for the loss of artistic mediocrity in a world saturated with stock images.
Artists are adaptable, and should be doing a lot more than selling robot images to stock art collections anyway. Time to level up. Nothing wrong with Ai keeping us on our toes.