I suspect some amount of long form writing will go the way of code - long form writing for the purpose of consumption by other AIs. Writing as a means of exchanging qualitative information, with no regard for how the reader will feel about it (beyond understanding what the words mean). Not everything can be distilled into data, but this doesn’t mean it is beyond the reach of LLMs.
On the other hand, long form writing for human consumption seems like it may evade LLMs for much, much longer.
What makes you think it will take a long time? AI seems capable of imitating any writing style if prompted to do so already, and I think it will get better on this quickly since the AI writing style is a main focus of AI labs right now. I can see no reason at all to believe this is a matter of years still, more like a few months.
The style you refer to is the "container" of the writing. The medium. Like the specific encoding of the message. What @arctic-true was talking about was the "content" of the writing, which is bounded from above[1] by the information content of the prompt.
So, I'm not sure if it's a question of time at all: if a LLM text contains some piece of information beyond the information that went into the prompt, where does this "extra" information come from? [Note, I'm not thinking about facts which could trivially come from the training corpus, I'm thinking specifically as information in the sense of intended message from sender (author) to receiver (reader)]
You can have a great “writing style” and still put together really crappy long-form work. The problem is that AI writing, particularly creative writing, is too repetitive, too predictable, too trope-laden.
All of the things you say are very true in the near term for short form writing - a page or two of Claudeslop will probably be much easier to swallow in a year or two than it is now. But I don’t see a path to fully AI-generated novels or long-form investigative journalism becoming mainstream in the next couple of years.
On the other hand, long form writing for human consumption seems like it may evade LLMs for much, much longer.