It would be enlightening to compare John Updike to some paragon of science fiction writing. Unfortunately no such paladin offers himself, so we'll have to make do with a composite.
What qualities make a great science fiction writer? Let's look at it objectively, putting aside all that comfortable bullshit about the virtues authors are supposed to have. Let's look at the science fiction writer as he is.
Modern culture, for instance. Our SF paladin is not even sure it exists, except as a vaguely oppressive force he's evaded since childhood. He lives in his own one-man splinter culture, and has ever since that crucial time in childhood--when he was sick in bed for two years, or was held captive in the Japanese prison camp, or lived in the Comoros Islands with monstrous parents who were nuts on anthropology or astronomy or Trotsky or religion.
He's pretty much okay now, though, our science fiction author. He can feed himself and sign checks, and he makes occasional supply trips into the cultural anchorage of SF fandom, where he refreshes his soul by looking at people far worse off than he is. But he dresses funny, and mumbles to himself in the grocery line.
While standing there, he doesn't listen to the other folks and make surreptitious authorly notes about dialogue. Far from it: he's too full of unholy fire to pay much attention to mere human beings. And anyway, his characters generally talk about stuff like neutrinos or Taoism.
His eyes are glazed, cut off at the optic nerve while he watches brain-movies. Too many nights in too