Regardless, the human generating and publishing these images is obviously responsible to ensure they are not violating any IP property. So they might get sued by Disney. I don't get why the AI companies would be effected in any way. Disney is not suing Blender if I render an image of Mickey Mouse with it.
Though I am sure that artists might find an likely ally in Disney against the "AI"'s when they tell them about their idea of making art-styles copyright-able Being able to monopolize art styles would be indeed a dream come true for those huge corporations.
1) the artist is not literally copying the copyrighted pixel data into their "system" for training
2) An individual artist is not a multi billion dollar company with a computer system that spits out art rapidly using copyrighted pixel data. A categorical difference.