It depends on how you define art. Creativity and intelligence are highly correlated, so if AI capabilities (intelligence) keep going up, it's only a matter of time until AI becomes very good at creating art that is enjoyed and consumed by humans.
On the other hand, with a bit of semantic sleight-of-hand, you could re-define art so that it only includes things made by humans, and try to artificially keep the price high that way. But I don't think it will work the way you expect it to. Rather, art made purely by humans will become a status symbol and it will be expensive not due to being technically superior, but due to its relative scarcity compared to AI-generated art. And the market for it will be much smaller than today, due to the overabundance of AI-generated art.