Earlier quoted context omitted.
Every waking second humans are training on what they see in their surroundings, including any copyrighted works in sight. Want to compare untrained AI fairly? Compare their artistic abilities with a newborn.
No. That is NOT what humans do unless you somehow learn grammar without going to school. Most of a human's childhood is spent learning from their parents so that they can move about and communicate at least a little effectively. Then, they go to school and learn rules, social, grammar, math, and so forth. There's some learning via copyrighted works (such as textbooks, entertainment, etc.), but literally, none of this…
That's not true at all. Any works in the public domain are not copyrighted, and there are things that are not copyrightable, like lists of facts and recipes.
Generative AI could be trained exclusively on such works (though obviously it would be missing a lot of context, so probably wouldn't be as desirable as something trained on everything).