Oh I see, I thought you were quoting https://metr.org/blog/2025-07-10-early-2025-ai-experienced-o... "Measuring the Impact of Early-2025 AI on Experienced Open-Source Developer Productivity"

Which shows that LLMs, when given to devs who are inexperienced with LLMs but are very experienced with the code they're working on, don't provide a speedup even though it feels like it.

Which is of course a very constrained scenario. IME the LLM speedup is mostly in greenfield projects using APIs and libraries you're not very experienced with.