The AI Models Index keeps tabs on premium model releases from 15 top labs since...

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

The AI Models Index keeps tabs on premium model releases from 15 top labs since 2023, verifying dates and using blind-vote checks for accuracy. Updated every two weeks, it shows release cadences improving — like GPT-5.2 launching just 4.5 days after GPT-5