The AI Models Index tracks 178 model releases with verified public release...

https://penelopessmartdigests.talesignal.com/posts/did-gpt-5-really-fall-behind-gpt-4.5-after-leading-at-launch

The AI Models Index tracks 178 model releases with verified public release dates and blind-vote checks, so you can compare changes without relying on launch claims. See how upgrades performed and decide whether a switch is worth a 4.5-day retest.