OpenAI's GPT-4o (May 2024)
OpenAI released GPT-4o, offering GPT-4-class intelligence at half the API price and double the speed. It shipped eight months after GPT-4 and quickly became the default model for developers.
Developers migrated en masse; OpenAI later cut cache-read rates to match demand.
Established the pattern of mid-generation efficiency drops resetting model pricing.
Opus 5.5 repeats the move: Fable-level capability at 40% lower running cost, two months after Opus 5.
