Author here. In short there are 4 different metrics:
- METR's time horizon
- TrackingAI's offline cognitive test
- Humanity's Last Exam, and
- ARC-AGI-2
that have lasted longer than 2 years (though ARC-AGI-2 is now saturated).
When plotted in the linear domain, they all have an exponential (hockey-shaped) curve, but the interesting thing is that the bend happens right at Q4 of 2025 (right when Gemini 3, Opus 4.5, GPT 5.2 all come out).