Fair use, the crux of the issue, tends to be complex to adjudicate. For it to be a thing, it needs to be checked on many criteria. Being used for education is one such criteria. (And it is education, not just "teaching". One could argue education has having a human destinatary as a necessary condition) However, there are other conditions. The most important being that it is transformative and it doesn't replace the original. Using a given artist's work to train an AI, not only allows the AI to draw, but also allows the AI to replace the artist, not just on the generic, but on the specific. An AI trained on a given artist, can perfectly mimic that artist's style, making the artist themself superfluous. It will have to reach the courts, but from existing precedent, it seems artists have a case with existing laws. All of them, not just artists putting their work behind paywalls.