The AIs generation isn't freeform completetion from the beginning of sequence token. It's not an average over all string seen. It's a conditioned generation based on the context (i.e. prompt).

If the context can be above average quality the result should be too as long as the AI is sufficiently smart. Especially if people iterate on the produced work to push it up in quality.

However if you don't have a good topic and don't iterate to improve the result then you get incredibly poor writing.