the LLM's themselves are making marginal gains, but the tools for using LLMs productively are getting so much better.
Recently I converted all the (Google Docs) documentation of a project to markdown files and added those to the workspace. It now indexes it with RAG and can easily find relevant bits of documentation, especially in agent mode.
It really stresses the importance of getting your documentation and processes in order as well as making sure the tasks at hand are well-specified. It soon might be the main thing that requires human input or action.
In fact, I built an entirely headless coding agent for that reason: you put tasks in, you get PRs out, and you get journals of each run for debugging but it discourages micro-management so you stay in planning/documenting/architecting.