I would disagree, but on,y considering I think this is not the right prompt to test against. Hence not the right question.
While you're asking to find creative ways to get rid of the player, I think what LLMs are unable to do (at this point?) is to come up with the idea of an aging mirror, let it sit for a while and only then get back to it when they met its attached character.
The dungeon master did not follow a track of events but rather picked interesting somewhat random contents and moments from the campaign and picked them up to create new story lines.
That doesn't seem like something an LLM would do easily.
Its not something an LLM would do with simple chatGPT type prompts, but it's something I can imagine building an agentic system to do. It's not trivial but seems feasible with current day LLMs.
If you design the system to have this exact quality (among many others), where clues are dropped earlier in the quest line for later quests. It's a matter of breaking up the prompts and iteratively refining the outputs.