Donald Antrim
The moment he wasn't lonely anymore he couldn't write poetry.
Either poetry just didn't mean as much to him anymore or his ex-loneliness was a prerequisite to writing it.
He wondered as he passed the rows and rows of poetry books at Powells Bookstore if all the poets whose books he passed were as lonely as he when he'd written his poetry.
Elizabeth Bishop was lonely, that he knew, and Emily Dickinson. The Beats must all have been lonely and had formed a clique to stave off loneliness, as The Imagists had earlier.
The theory that poets formed cliques because of their loneliness didn't hold, however, in the case of the Romantics, for instance. John Keats had his brother George and Severn; Wordsworth had his sister Dorothy: and Byron had Shelley and vice versa. Coleridge might have been lonely, it's true, but took hallucinogenic drugs to compensate.
It's possible that theories don't apply to poetry as they do to prose, due to the innately singular nature of poetry and the more collective nature of prose
The theory, for instance, that the style of the prose of a writer like Donald Antrim, a descendent the critics say of Anton Chekhov and Donald Barthelme, is all in the thinking, is far more sustainable.