Many magazines have closed their submission portals because people thought they could send in AI-written stories.
For years I would tell people who wanted to be writers that the only way to be a writer was to write your own stories because elves would not come in the night and do it for you.
With AI, drunk plagiaristic elves who cannot actually write and would not know an idea or a sentence if it bit their little elvish arses will actually turn up and write something unpublishable for you. This is not a good thing.
There are a few art sites that swiftly banned AI art before they got flooded (with Newgrounds and FurAffinity the most well-known).
Alongide the decentralised solutions you mentioned earlier, those sites should also come out okay once the dust settles.