It's pretty clear, because OpenAI has no clue what they are doing. If I was the CEO of OpenAI, I would have invested significantly in catastrophic forgetting mitigations and built a model capable of continual learning.

If you have a model that can learn as you go, then the concept of accuracy on a static benchmark would become meaningless, since a perfect continual learning model would memorize all the answers within a few passes and always achieve a 100% score on every question. The only relevant metrics would be sample efficiency and time to convergence. i.e. how quickly does the system learn?