But the appreciation of art itself could still be a spandel wouldn't it? It may be rooted in an "evolutionary purpose" historically, but the actual appreciation of art itself may not have any selection pressure associated with it.
When you find a persons physical appearance to be sexually attractive is it because you perceive that the particular physical qualities are highly correlated with successful mating and propagation of ones genes?
That a trait crops up and is successful has no correlation with "purpose" in a conscious sense. It is either successful or not and what ever intellectualization one attaches to that trait is irrelevant as far as evolution is concerned.
I would also assert that a connection between "art appreciation" and sexual selection is quite alive and well in modern times.