I don't understand why that's a downside.
> It's not a direct harm in itself
I don't understand how it's a harm at all.
For some it's demoralizing to know that your work will be broken down and atomized into language model mush, and the credit will go to the computer.
Yes, that was one of the things that I hope happens with the open source software I write.
> Would you be willing to do free work for a corporate entity whose entire business model is making sure they sit as a gatekeeper between your free work and others who would benefit from your work?
Sure, that's what doing SEO on one's own blog is, isn't it?
> For some it's demoralizing to know that your work will be broken down and atomized into language model mush, and the credit will go to the computer.
I think this is probably the crux: that writing is no longer discoverable because people aren't using search engines any more. It would be interesting to put some hard numbers on that. I reckon writing is still more discoverable (in absolute numbers) than it was when blogs first took off (over 20 years ago?)