Have you found LLMs to be good at metalinguistic abstraction? I have used them a little bit for lisp programming but never once have I seen them introduce macro.
Call it "vibe coding by tiller". Ha.
Also, I think of metalinguistic abstraction as something deeper than macros. At least not limited to macros:
"An important advantage of making the evaluator accessible as a Lisp program is that we can implement alternative evaluation rules by describing these as modifications to the evaluator program."