Sure, some of the people who currently pay for art will stick with human creators, but the majority won't. An average person who buys a magazine or a computer game or watches an ad won't care if the illustrations inside are human or AI made.
Which wont fundamentally classify as "Art".
Magazines those use high quality human artists production will continue to sell in more value, simply because, what they contain are always unique and new. AI fails to render anything new other than a mashup of existing patterns. Human artists can re-imagine and re-contextualise. AI cant' :)
But here, the legal system is going to bit anyone who would fully use AI as they would be zero copyright or intellectual property rights attached with anything an AI creates unless they can prove that it came as a product of training on data they own and produced alone. If it involves general data online there wont be any intellectual rights they can claim for the creation. Hence making each copy of that worthless.