The lesson we should take from GPT-3 is that we spend way too much time reading text that isn't really saying anything, and/or failing to find meaning in what we read. It's a neat trick, and I think it could absolutely replace much or most of the writing on the internet today. But is it
good writing? No, not really. At least, not in the sense of writing as producing anything more substantive than slick prose with a vague, meandering context running through it.
I think the next step (say, being able to produce short stories with actual literary value) will be substantially more difficult, mostly because it's substantially more difficult for human writers too. It takes learned abstract knowledge and deliberate intention to write something that's coherent and engaging and longer than a few hundred words, and that skill is separate from the intuitive prose generation ability that's essentially unconscious for practiced writers and comes easily to many avid readers (i.e. trained on a large corpus) who take up writing.
It will be interesting to see how producers of actual substantive content incorporate these tools into their processes, if at all. I guess I can imagine using it to generate descriptions, for instance, but how does it do with dialogue? Probably not very well.