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

https://stateofseo.com/understanding-the-difference-between-point-releases-and-new-generations-in-large-language-models/

The AI Models Index keeps tabs on premium releases from 15 labs since 2023, with verified dates and blind-vote quality checks, refreshed every two weeks. In 2026, we've seen an average of one new release every 4.5 days—a 56% faster rollout pace