I am not talking about using an LLM to make code reusable in the sense youre arguing.

My point is that the very act of training an LLM on any corpus of code, automatically makes all of that code reusable, in a much broader semantic way rather than through syntax. Because the LLM uses a compressed representation of all that code to generate the function you ask it to. It is like having an npm where it already has compressed the code specific to your situation (like you were saying) that you want to write.