What image generation models cannot replicate is the personal experience of the people who make art.

I'll give you an example. One of the most talented designers I employ is a nature lover and a bird-watcher. She has a unique mental profile, as well, in that she's synaesthetic between colors, letters and shapes. In other words, she has a unique neurological structure, coupled with high artistic talent, and an interest in a very particular realm of science.

What makes her design worth $150/hr is not just that her execution is often flawless. It's that you would not, and could not, think of a prompt which would make an AI model produce a new piece akin to anything she would think of in her process of thinking about what to draw. Could you have it replicate something she did? Obviously. But that means what you're doing is in the long tail, and in terms of quality and originality, is by definition somewhere in the mediocre.

And that's probably fine, for whatever you're doing. But an AI with any kind of prompt would not come up with a Studio Ghibli clone, if Studio Ghibli hadn't existed.

So you shouldn't imagine that you are actually getting any original output out of an LLM, regardless of how cleverly you design your prompts. But moreover, don't flatter yourself to think that you have the ideas to feed to a prompt which would generate truly original content and break free of the shackles imposed by its training. That is an illusion. Very few people have the propensity for generating new visual ideas, and that's why they're still in high demand. But their originality stems from their unique and impossible to replicate experience as individuals who have their own visual/mental map of the world.