As another commenter mentioned, the point of the story from Borges is that a perfectly detailed map is rather useless, because you need abstraction (it's a repeating theme in some other stories from him like the Library of Babel, and Funes the Memorious). LLMs are likely already able to exhaust the conceptual space for any given field, but some judgement is still going to be required about what to pursue. In biology and other fields this problem is even bigger because experimentation is so difficult and expensive.

The process of judgement and resource allocation will still be human for quite a while, but it's quite likely some humans will outsource their responsibility to AI to cut corners.