The key to understanding this poem are the lines "he sang his didn't he danced his did", in other words, he spoke of grand things, but what he actually did was completely, and much less grand.
This dichotomy between words and action is echoed in virtually every stanza of the poem.
It has echoes of T. S. Eliot (Prufrock and The Wasteland).
And the wonderful musicality of the words and rhythm that mask this unfulfilled potential make it all the more poignant.
