A little known fact about William Blake is that his poems in Songs of Innocence and Songs of Experience were published in a painted form. As the article William Blake and the Music of the Songs explains:
One of the characteristics of Blake’s work that makes it so interesting—and so challenging to study—is its use of diverse media. Since Blake believed that “Painting, as well as poetry and music, exists and exults in immortal thoughts,”  it is appropriate that he used each of these “sister arts” to express his artistic vision, pursuing, as he put it in a letter to George Cumberland, the vocations of “Poet Painter & Musician as the Inspiration comes” (qtd. in Bentley, Blake Records 95).  And yet, literary scholarship has not always attended to Blake’s multi-media mode of practice. During the first half of the twentieth century, indeed, readers commonly considered only Blake’s written words when interpreting his poetry, and whole books of academic criticism were written containing hardly a reference to the visual and verbal designs that are such crucial parts of the illuminated writing.  But in the past thirty years or so, following the guidance of critics like David V. Erdman, W. J. T. Mitchell, and the editors of the William Blake Archive, Blake scholars have come to insist that the poetry must be read in its original engraved and painted form rather than in the barren typescript versions still presented in many literary anthologies.
I'm hoping someone here could explain why most publishers made the decision to only publish the text of the poems and ignore the artwork associated with those poems.