The AI Models Index tracks premium model releases from 15 labs since 2023, with...

https://deansinspiringperspective.hexaforgey.com/posts/what-happened-to-gpt-5-vs-gpt-4.5-lead-over-time

The AI Models Index tracks premium model releases from 15 labs since 2023, with verified dates and blind-vote accuracy checks. Updated every two weeks, it shows how releases speed up—like GPT-5.2, which reached trusted testers 4.5 days faster than GPT-5