Writers can by quite lazy.
They want ready-made conceits to drive the narrative and carry an emotional charge, and they search for accessible metaphors to do the work of universalizing for them their (usually) much-too-personal content.
Golf doesn't give the lazy writer any of that.
It doesn't mean what it once did; it's no longer (as it was in the jazz age, for the Great Gatsby, or after WWII for a safe and growing middle class) a clear and resonate signifier/symbol of much anything at all, and certainly nothing with an emotional charge or metaphorical import.
Golf is also such a game of introverts, such a quiet game without external battles or violence, that in an increasingly harsh and extroverted culture it doesn't serve well at all as a dramatic vehicle, especially for the lazy and/or self-absorbed writer.
Finally: besides being lazy, many writers simply lack much talent. They find it easier and more satisfying to write about themselves (essentially, in thinly-veiled autobiographies) than to get into the heart, mind and motivations of a golfing character they have created from scratch.
As a critic said once: a lot of modern writing isn't even writing, but merely puddles of spilled sensibilities. I guess that, less than ever before, those sensibilities don't revolve around or even involve in the least the game of golf.
Peter