I assume you are correct but how can we know rather than assume? I am not sure we can, so why get worked up about "internet died in 2021" when many would claim with similar conviction that it's been dead since 2012, or 2007, or ...
You are making a claim that somehow someone was sitting on something as powerful as ChatGPT, long before ChatGPT, and that it was in widespread use, secretly, without even a single leak by anyone at any point. That's not plausible.
Twitter has been accused of being full of bots long before ChatGPT appeared. For 140 symbols, a template with synonyms would be enough to create mass-generated content.
