I like the moody darkness here. The picture suits it well.
The last stanza obviously ties in the setup from the rest very well.
Oddly enough, I think you could replace the last word 'poetry' with a great many other things and the statement against those things would be strong as well.
Shit. I meant to reply to this, and then upvote it, and left it for later, and somehow it slipped through the cracks.
Now, the final word, replacing it with anything that is "literature/art" is easy. Because you don't actually change the message much.
But what else could we change it for that is interesting? "Religion," especially a sacrifice-based one as Christianity likes to depict itself these days is very apt, almost too apt.
And then we can look at what Marxism spoke of, when the result of the work is more important than the work itself. Capitalism. "Work" itself, perhaps. "Money"?
An interesting topic to think of. We can think of it as the army, but there are all sorts of armies where we serve in our lifetimes.