> because writing code used to be the slow part

I don't understand how people have that stated as a fact. Coding was never the slow part. Neither pre-llm, nor now. How it needs to be done is software engineering. And that corresponds now to the "thinking" part of llms, so unless you are making the llm "think in lisp" its not useful. How would that even work. training data to be completely in lisp ?

> Lisp programs are often much more concise because macros let you abstract away recurring patterns and make them part of the language itself

functions ?

> So the bigger the program gets, the bigger the difference. In my own experience the apps I've built in Common Lisp end up about six to seven times shorter than the Python versions

By that logic writing code in this concept language made up completely of symbols would take you even further ( https://github.com/artpar/guage ) but in practice it doesnt because llms arent trained to that extent on this.