[causi]

one might say that a great poet using only a few words might capture a landscape better than a painting, but if our culture drifts toward a visual one where poetry is no longer understood we cannot say that the medium itself degraded.

That has little to do with the medium. If the painter takes as much effort as the poet, and the viewer as much time and effort as the reader, just as much information and emotion can be gleaned from the painting as the poem.

[jacobr1]

The medium can matter in both cases, in the sense that the medium is not just the format, but also the cultural context of interpretation. There can be subtleties in word choice that evoke shared stories, or word connotations or otherwise make reference outside the work itself. You can have the same references in the form of visual symbols, stylistic choices or more. The viewer/reader must make much more effort to gain that cultural context for interpretation, which may very well be lost or degraded over time.

I would posit that while a painting has can be very high context, that the tendency is for poetry to be even more context dependent. Transplanted outside its native culture, I suspect visual works (again, on the margin) can be grasped with more depth by the viewer than than a reader of the (on the margin) poem.