What you describe is "Didactic Art" that is, art whose message is plainly apparent. My take is that Didactic Art is in fact quite important, it serves society in many profoundly important ways.
That Napoleon was eventually defeated was the result - in part - of a painting that depicted a giant, rather inattentive, absent-minded giant eating a human corpse like a candy bar.
However, the Nova Scotia College of Art and Design is heavily into what Bonita calls "Art with a Capital 'A'". More or less, that's art that only other artists understand, as well as art historians. I learned a great deal about art history while she studied there, and attended a few lectures, spent time in its small but excellent library; again there are many important reasons why we have Art with a Capital "A".
Escher was reviled by the other artists of his day because they regarded his work as revoltingly ugly. Consider that at the time we had stuff like Bauhaus and Art Deco.
I at one time had the email escher@apple.com
Hilarity ensued because everyone thought I was Christopher Escher, Apple's chief public spokesman. In reality I was hired as a contract script monkey for MacTCP, but I worked my way up by debugging its broken test tool strm_echo.