If you use GPT-4 day-to-day, you've probably encountered this sense of a capability wall before. The point where additional prompting, tweaking, re-prompting simply doesn't seem to be yielding better results on the task, or it feels like the issue is just being shifted around. Over time, you develop a bit of a mental map of where the strengths and weaknesses are, and factor that into your workflows. That's what writing with LLMs feels like, compared to working with a professional writer.
Most writers have already realized that LLMs can't write in any meaningful way.