It makes sense when you consider LLMs don't generalize very well, so they're heavily dependent on how good (how varied as well as how high quality) the training data is
Well it might explain why pro-Claude vs pro-Codex people keep talking past each other on this forum. I see people all the time assuming that anybody who likes Codex must be some sort of bot because of their own biases, but I work almost exclusively in Rust and find Codex extremely competent (and a much better overall engineer), don't trust Claude/Opus at all... but I see in this bench it scores lower on TypeScript etc. than Opus does.