OpenAI’s GPT-5 Dip; Why Agents Are Hard to Evaluate

Before we get into today’s column, Friday’s story from Sri and me confirmed what many had been hypothesizing since OpenAI’s release of GPT-5 in August: ChatGPT’s growth hasn’t been as strong as OpenAI hoped.

The story is more nuanced, obviously. The chatbot has hit new highs in terms of weekly active users—910 million, to be exact as of earlier this month. But OpenAI leaders had hoped to hit 1 billion WAUs by the end of 2025.

A slowdown in growth began with the rocky release of GPT-5 last summer, in which a number of users complained that the model had a smaller-than-expected jump in capabilities and a colder personality than its predecessor GPT-4o.

OpenAI leaders told investors last week, however, that ChatGPT growth has picked back up again this year, thanks to the GPT-5.1 and GPT-5.2 updates, which gave the model a warmer personality and better performance on workplace-related tasks. They expect WAUs to hit 2.75 billion by 2030, meaning that approximately a third of the world will be using ChatGPT on a weekly basis by then.