I was recently thinking about that very thing in terms of illustration.
Readily available and cheap stock photography in addition to digital cameras killed much of the custom illustration business. Instead of paying an illustrator for a day’s work, there was probably an inexpensive or free photo immediately available that would work.
Image-generation AI tools might get art directors and designers to consider using AI illustrations where they previously might have used stock photos. As people get more used to seeing illustrations, I can imagine exactly what you described: actual artist-produced illustrations going up in value as being seen as the real thing instead of an imitation.
Similarly, natural diamonds and emeralds are still worth more than the synthetically produced versions, which might be more perfect, but have no character or history behind them.