That's a product problem, not an ML problem. If I'm making a tool for doctors, I don't need to surface the exact scientific fact the LLM recalled from memory,

That's a product problem, not an ML problem. If I'm making a tool for doctors, I don't need to surface the exact scientific fact the LLM recalled from memory, I can design an interface that surfaces verbatim text from sources based on the LLM's understanding of the situation. No serious product should be surfacing a ChatGPT style chat window to the user, it's a poor UX anyways with awful discoverability.