How does this handle modern art which is very incompressible too? If we take your hypothesis then one could say modern art isn't good, which some do say.
Even traditional art often tries to do more than compress concepts, it tries to express the inexpressible.
Linguistic determinism/relativity (Sapir-Worf, etc) explains some of it. People can FEEL that their thoughts are being constrained by language, but they don't know how to express that and maybe don't even consciously realize that it's their real problem. They just figure out that art makes it feel a little better so they do art.
Here are some example 21st century painters: https://medium.com/@John_Dalton/living-masters-the-top-13-re...