Well, the simplest of 'literotica' is just an uncensored, fiction-writing friendly LLM (Fine tuned on fiction/RP, rather than truthful and friendly responses).

NovelAI has been around for a long time, after AI dungeon died in flames. They sell exactly that. They also did the first powerful fine-tune of SD. Now they've got a H100 cluster, and are committed to training a GPT3.5 equivalent.

These companies have difficulties getting investor funding, the good side is however, AI products are so useful, users have an extremely high intention to pay. So these no-investor companies can pure bootstrap themselves with high profitability and high growth.