The reasoning you need to know:
Humans learn Art very differently from AI
Humans witness Nature, Real Life, mostly, in order to be inspired - which is often where they spend most of their time.
Lame Artists may try to copy other Artists - their ideas and styles - and from my observations, these always tend to end up ultra mediocre.
Talented Artists - the ones that are of interest for AI to copy mostly from - acquire their style from research, their own experimentations, inspection into Natural effects; patterns galore, lighting, and so on. And if they study other people's work, it is part of their curricula, and very limited. They know that "too many cooks spoil the broth", so they limit their sources. Copyrighted instructional books (that they paid for) or treatises at the public domain.
AI does *not* need to know: platonic shapes, theory of light and shade, human and animal anatomy (body landmarks), relative proportions (head-height cannon), 1,2,3, n-points perspectives, body types: aging, distribution of fat, material science; pigments, colour theory, composition ... and so on, in order to create more convincingly. Humans do. Can you see the difference?
The more an artist research and learn from various related fields, the better their results, usually. It is a very conscientious discipline, a long strategical game.
About style. This is often one only and the particular mannerism of the artist, evolved from years of practice, of trials and error discovering what works best. Finding a voice. Not by consciously assimilating others. Unless mediocre. People with their own style tend to attract more interest from others than the generic. It becomes their hallmark, their trademark.
The idea that a machine can be excused digesting billions of images, because humans "learn" by merely looking at photos and art from magazines or the web - is complete fallacy. We do not. We have shitty photographic memory and just-in-time analytical processing. We are pretty crap at learning. Keep repeating the same mistakes. Our brains are lazy as fuck, always finding an opportunity to save energy ... Hence the "AI learns Art just like Humans do!" ... a phrase that keeps getting repeated, again and again, mindlessly by idiots.