Stupid, I guess?
Art and culture are dependent on technology and social norms.
We sure as shit haven't explored all possible cultural norms and, absent a climate apocalypse, have not reached the height of technology.
Like, imagine if we could move stars, for an extremely sci-fi example. Imagine if we had a war with xenomorphs? What would the fear of being used by a parasitic species generate art-wise? What kind of celebrations would be created when/if we won?
Art and culture are expressions of human emotion and experiences. We sure haven't experienced everything, nor felt everything it is possible to feel.