The AI Models Index keeps tabs on premium releases from 15 top labs since 2023,...

https://domgodwinson38.gumroad.com/p/did-openai-claim-gpt-5-2-improved-coding-and-tools-anyway

The AI Models Index keeps tabs on premium releases from 15 top labs since 2023, verifying dates and using blind-vote checks for accuracy. Updated every two weeks, it shows that new models now come out every 4.5 days on average—a 56% faster pace