A natural language is a living thing. Every day each speaker adjusts his model a tiny bit. This has advantages but also some serious disadvantages which is why technical writers are very careful to use only a small subset of the language in their writing.

For true natural language programming we'd need to develop a language for reliably describing programs, but this doesn't exist in the language, so why would it exist in the LLM models? It will never exist, unless we invent it, which is, of course, exactly what programming languages are.

Natural languages are not invented. Written scripts are said to be invented, but nobody says a natural language like English or French is invented. It just happened, naturally, as the name suggests.

If natural language were the end goal then mathematics and music would use it too. There's nothing stopping them.