Beauty is (a heuristic for) truth, truth beauty
beauty in flowers is a code between species - insects and flowers
Sometimes leaves or barks are beautiful to us, but flowers reliably are
Sometimes something evolves locally, like a peacock's tail, that's beautiful to us, yet rare.
The code has to be hard-to-forge for competing flowers, but easy to decode for the right insect
Compared to roots or leaves the arms race yields complex genes for flowers
There's is a large gap between flower species and not much shared knowledge
One human, in terms of knowledge and individuality is like a separate species
Artists have to send messages across this gap - larger than flower-to-bee distance
We can exchange messages that are predetermined by culture and genes or we can invent something new. In the latter case we should strive for universal truth. This may be a proximate reason humans ever did so.
Counter: Aliens might have art that we can't understand. That's true, our art is indeed parochial, but a good first approximation to something universal
Is there no such thing as better Art? We don't need a waste basket in the office?
But what becomes the norm of that culture then? If you can't improve a tradition, what do artists aspire or go to school for then?
Choice should produce something less random than the options you choose from