I totally agree. I remember the June magic as well - almost overnight my abilities and throughput were profoundly increased, I had many weeks of late nights in awe and wonder trying things that were beyond my ability to implement technically but within the bounds of my conceptual understanding.

Initially, I found Codex CLI with GPT-5 to be a substitute for Claude Code - now GPT-5 Codex materially surpasses it in my line of work, with a huge asterisk. I work in a niche industry, and Codex has generally poor domain understanding of many of the critical attributes and concepts. Claude happens to have better background knowledge for my tasks, so I've found that Sonnet 4.5 with Claude Code generally does a better job at scaffolding any given new feature. Then, I call in Codex to implement actual functionality since Codex does not have the "You're absolutely right" and mocked/placeholder implementation issues of CC, and just generally writes clean, maintainable, well-planned code. It's the first time I've ever really felt the whole "it's as good as a senior engineer" hype - I think, in most cases, GPT5-Codex finally is as good as a senior engineer for my specific use case.

I think Codex is a generally better product with better pricing, typically 40-50% cheaper for about the same level of daily usage for me compared to CC. I agree that it will take a genuinely novel and material advancement to dethrone Codex now. I think the next frontier for coding agents is speed. I would use CC over Codex if it was 2x or 3x as fast, even at the same quality level. Otherwise, Codex will remain my workhorse.