What do you mean "no way"? We've written long texts for as long as we've been writing as a species.
it's not that it's completely unbelievable, but I could see people having doubts considering:
1. AI exists and is widely used 2. A person only has so much bandwidth. If they put out 10 docs in a day, did they really hand write them all?
Not GP, but consider the view from the inside of a feckless pleb's skull. Effort is to be avoided, so its needless expenditure is unrelatable.