My father-in-law did a fair amount of editing back in the day (on paper, with red pencil/pen). He said that, when you saw something that had "blood" (red) all over it, that meant it was good. When things are bad enough, it becomes hard even to edit it.

It may not be just that people don't edit LLM output. It may be that the stylistic blandness is so pervasive, it's just too much work to remove. (Yeah, maybe you could do it. But if you were willing to spend that kind of effort, you probably wouldn't have an LLM write it in the first place.)

Airplane meme: you only see the bad LLM or obviously LLM-assisted writing.