Why poetry? I mean, why do we do this?
We take aesthetic pleasure in words, what language does?
That, and something else. With language we acknowledge, define, order, shape what we experience. This is a techne intimately fused with that which it represents. With poetic speech we "surround ourselves with domestic utensils, the warmth of the hearth" (Mandelstam's description of the poetics of Acmeism - "domestic hellenism". He was doing this in deliberate contrast to the more otherworldly & abstract qualities of Russian Symbolism).
The equilibrium of artifice - craft, techne - and nature is at the root of civilization.
So perhaps we can recognize a certain solemn (&/or playful) objectivity, disinterestedness, at work in poetry - a reflection or emanation of the poet's serious effort to follow & express truth - the poet's equivalent of the philosopher's or scientist's activity.
The image of "the city" in art (as I said, I'm reading about medieval Siena), representing an ideal of equilibrium between know-how & nature, individual & community. (And hidden within every image of the city is that of a garden.)
The word bears the techne of a global equilibrium (Mandelstam also foresaw this). When he talked about the poem as "like unto an Egyptian bark of the dead, carrying everything necessary for life" - he was talking about the word-itself as a sort of Noah's ark.
The curious focus in the American long poem on the local, the city. The unavoidable and only shared "here & now" where any real equilibrium (political, cultural, natural) becomes possible.