Depends on what value you are talking about. Economic value? Definitely.
Artistic value? No. Artistic value is subjective. It is based on the creator and the beholder. Yes, someone can value the AI artwork more but that isn't because they devalued Studio Ghibli's work.
And some people would value Studio Ghibli's artwork more because it has been made by Studio Ghibli. But that doesn't detract any value from the previous person who valued AI artwork more.
Art is subjective and it is given value by who beholds and cherishes it.
I agree that art is subjective, but in my view, what AI generates is not art. Art is something made by human beings for human beings.
By virtue of being subjective, you can't decide what is art or not. You can say for me this isn't art. And there are plenty of "art" made by humans that I wouldn't consider so, but someone does hence they are art.
It's true, I think it's a matter of belief and personal choices. what is art for me may not be for you and vice versa.
That is why it is important to study aesthetics, as it is one of the only ways to truly understand what art actually is.
I think that aesthetics are completely unnecessary, since one of the principles of art is to provoke sensations and feelings. If no one felt anything, the concept of art would never exist.
Sorry, but I feel like you don't know what aesthetics is