I think there is another aspect worth considering here: why someone uses AI in the first place.

Not everyone uses AI because they don't want to think or because they want to produce more content with less effort. For some people, there can be very personal or even medical reasons. Difficulties with concentration, memory, language or simply getting thoughts into a coherent written form can make writing much harder than the actual thinking behind it.

In that case, AI doesn't necessarily replace the author's character or thinking. It can become a tool that helps translate thoughts into words.

And that makes me wonder whether the more important question isn't necessarily "Did AI write this?", but rather "Whose thinking is behind it?"

The interesting part is that the final text might be much more polished, while the thoughts, experiences, opinions and even the strange detours behind it are still entirely human.

Perhaps AI won't necessarily remove character from writing. Perhaps it will also allow some people to express a character that otherwise wouldn't be visible in their writing at all.