What has only clicked for me in the last week for some reason is that stress is more tied to natural speech than prosodic rules...
But I think it is useful to have the iambic beat in mind when reading Shakespeare, e.g., cos you get more of a sense of his rhythmic diversions from it...
I do think poetry is more like music than I realised, although that can be a misleading comparison - but as with music, you want to fall in love with it on an instinctual level BEFORE learning about time signatures and intervals and all that.
This sort of thing is obviously not as SIGNIFICANT as the waste land but I think it helps you fall in love with poetry, it's the clever rhythms, rhymes, alliteration etc...