Capacity appears to be inline with others: https://old.reddit.com/r/Ultralight/comments/1li5rxw/20000ma...
https://www.theverge.com/2024/12/23/24326077/i-asked-chatgpt
LLMs are pretty good at imitating styles, if asked to do so. It's just their default style that's easy to recognise.
(You are probably right in everything you say! I just wanted to point out that style of an article isn't necessarily a giveaway.)