That's true and I fully agree. I don't think LLMs' progress in writing a toy C compiler diminishes the achievements that the GCC project did.
But also we've just witnessed LLMs go from being a glorified line auto-complete tool to it writing a C compiler in ~3 years. And I think that's something. And noting how we keep moving the goal post.
GP: "it didn't write a C compiler, it copied other compilers. Writing one from scratch is a lot harder."
You: "but look! It wrote a C compiler!"