The AI Models Index tracks premium 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 releases from 15 labs since 2023, with verified dates and blind-vote accuracy checks. Updated biweekly, it shows release speeds improved by 56%—now just 4.5 days between updates. Recent highlights include GPT-5