After Pope, in the beginning of Romanticism, people developed the idea that imagination rather than reason was a special form of knowledge and its best expression is through poetry. Therefore, poetry should not try to do the stuff that mere prose does: convey information or make arguments about ideas.
Robert HassYou only had widespread literacy and books that people could afford in the middle of the 19th century. Did more people read poetry at the turn of the 20th century when there were about fifty million people?
Robert Hass