Their recent paper suggests the active user base is continuing to grow consistently with consistent/growing usage based on how long they've been using the app.
https://cdn.openai.com/pdf/a253471f-8260-40c6-a2cc-aa93fe9f1...
https://cdn.openai.com/pdf/a253471f-8260-40c6-a2cc-aa93fe9f1...
Show me an independent study.
Anyway, attention == ads, so that's ChatGPT's future.