Reading that passage a few more times I think Updike should have stopped after his first sentence. A delicious image spoiled by a needless need to elaborate.
Rich --
Disagree emphatically.
Here's the passage, again: "My golf is so delicate, so tenuously wired together with silent inward prayers, exhortations and unstable visualizations, that the sheer pressure of an additional pair of eyes crumbles the whole rickety structure into rubble. 'What is the caddie thinking' keeps running through my mind, to the exclusion of all else...Imagine writing a poem with a sweating, worried-looking boy handing you a different pencil at the end of every word. My golf, you may say, is no poem; nevertheless, I keep wanting it to be one."
The "sweating, worried-looking boy" handing him pencils makes the whole passage rise, well, ABOVE the "poetry" of the first sentence, as it grounds it here on earth.
By the way, I am vain enough to think I could improve that first, poetic sentence.
Had I been Updike's editor, I'd have said: "Don't you think, John, it would be better this way: 'My golf is so delicate, so tenuously wired together [DELE: with silent inward prayers, exhortations and unstable visualizations], that the [DELE: sheer] pressure of [SUB "just two more eyes on it" for "an additional pair of eyes"] crumbles the whole rickety structure into rubble'?"
Thus: "My golf is so delicate, so tenuously wired together, that the pressure of just two more eyes on it crumbles the whole rickety structure into rubble."
Better? I think so. Still poetic, but much more efficient.
As for your "Why 'poet'?" question: I don't think he's revealing anything about his self-assessment as a writer. He wrote poetry from beginning to end, and I doubt if he thought it was mediocre.
He chose the poet/poem image because it alone allows him to get where he wants to get: to "My golf, you may say, is no poem; nevertheless, I keep wanting it to be one."
My golf is no novel? That doesn't work.
My golf is no essay? No book review? No stage play? Those don't work.
Nothing works except "poem."
Dan