I think grandparent comments were talking about how Codex designers try to push LLMs to displace the interface to code, not necessarily code itself. In that view, code could stay as the execution substrate, but the default human interaction layer moves upward, the way higher-level languages displaced direct interaction with lower-level ones. From a HCI perspective, raw computational efficiency is not the main question; the bottleneck is often the human, so the interface only has to be fast and reliable enough at human timescales.