To change my mind I’ll be satisfied with a thorough description of the domain and ideally a theory on why it does poorly in that domain. But we’re not talking LLMs here, we’re talking opus4.5 specifically.

A theory besides... not enough training data? Is it even possible to formulate a coherent theory about this? I'm talking about customizing a widely-used build system, not exactly state-of-the-art cryptography. What could I possibly say that you wouldn't counter with "skill issue" (which goes back to the author's point)?

If you say it's demonstrably impossible that someone can't be made more productive with opus4.5, then it should probably be up to you to demonstrate impossibility.