That border is determined not as much by ground truth, as by people's sentiment. As such, many famous artists and creatives never succeed navigating - their contemporaries would call them crazy, and then decades or centuries later, the border shifts, and suddenly they're remembered as greatest creators of their era.
Until an AI can have desires or experience life it cannot tell a story.
Even if it could it is questionable if such alien experience qualifies as story.
It can retell stories. It can swirl around extant media like a child playing with its dinner. It cannot blend in its own lived and new perspectives which is what gives new art value.
It's interesting to compare your opinion with Andrew Wiles quote:
> Perhaps I could best describe my experience of doing mathematics in terms of entering a dark mansion. You go into the first room and it's dark, completely dark. You stumble around, bumping into the furniture. Gradually, you learn where each piece of furniture is. And finally, after six months or so, you find the light switch and turn it on. Suddenly, it's all illuminated and you can see exactly where you were. Then you enter the next dark room...