>>7673511
So art goes from being a spiritual practice to a dick measuring contest for a wealthy land owning gentry. The aesthetics have been tuned up to a visual peak but the subject matter has fallen into this pit of vapid, narcissistic, philosophically underwhelming emptiness.
However as those enlightened ideas progress, and the wealth of the land owners moves from domestic farming to international trade, banking and manifesting, cities are starting to get big. Trade means food can be exported and imported, populations are fluctuating but growing. With the enlightened thinking comes the disintegration of the cultural caste system based on religious beliefs from the medieval era. The spread of the printed word means that more people than ever can read and write and have reason to learn to read and write. This means the religious text is no longer the guarded property of the church and the land owners. The enlightenment takes further leaps into liberating the common people from these role of serfdom. Art follows and leaves behind the landed gentry as a subject. So artists take the realism and idealism they've culturally attained and turn them to other subjects. Some go back to nature, where the Romanticists indulge in the sublime and raw terrifying beautiful scale of nature. Some go to ideas like nationalism, where the Neo-Classicists explore ideas like the national character and civic philosophy. And some take the subject to the huddled masses, the urban poor, filling up the world at an alarming rate, in a school of painting called Realism.
The subjects like military, revolution, industrialism, poverty, race, exploration, nature all kind of hit the scene as the clashing and shoving ideological conclusions of the renaissance era and the western world's rapid changes arrive on scene. Mass conflict, political upheaval and hungry mobs follow.
So to answer OP's original question The 19th century feels like a sudden busy mess becuause it was. And the art reflects that