I.. I don't think they are generating the history on the fly for each individual playback. Probably just generating images based on the concept, iteratively tweaking until it conveys the message that is desired by the artist. You know. Like most artistic works. AI is another tool.
Not to say training data being copped from hardworking artists is good, but an ethically trained AI for image generation for this context is not necessarily evil if it is used in the context of executing the artist's vision in the way they deem necessary and sufficient. Relying on outside people can often cloud the vision of a project.
That being said, pay artists for their work, license if you want to train, and credit/royalties should be paid until copyright expires or the rights are purchased outright for a competitive compensation.