Art is the residue of culture on two levels.
In the first sense, art objects are the artifacts left over after all use-value has been extracted, i.e., when things have no further function they become Art. Pictures on a wall.
(Here the reader may insert an argument about design and craftsmanship and/or a counter argument about bad design.)
However in Level II of my alternate historicity, The Arts are the residue.
Lets say that Dark Ages newspapers had a monthly Arts section which covered everything from Hildegard von Bingen to Leonardo da Vinci.
Then later, during the Enlightenment, it became the Arts and Natural Philosophy page.
After which Science got it's own weekly publication, leaving us with the Art and Humanities magazine.
Until now: The Arts and Entertainment sunday supplement.
The point being that The Arts are always the residue of cultural ferment, calving off new areas of development. An interesting field of endeavor splits off and Art is left holding the spare parts bag.
Now. What if we split Entertainment off? After some bloody skirmishes, movies, TV, pop-music, yadayadayada, get their own section of the net, and The Arts gets the rest -- say Art and Culture. Opera, Symphony, Literature, Galleries, Museums, all the stuff that signifies sophistication to consummate 10%ers.
Then Culture can be excised. The historically significant art gallery and concert hall spectacles are all stuffed into convenient wallets and the surplus is renamed Arts and Ideas, where Ideas are what's left of late 20th century art.
So, ultimately Art is the leftover stew from whence Ideas bubble. When one of those New Ideas gains credence it becomes its own field leaving the unnecessary bits behind as The Arts. And without The Arts broth, New Ideas do not gestate.