Indeed, as did the much-missed Iain Banks. The Guardian's headline is tiresomely reductive, although of course that's no more than one expects from the press. I would suggest that Harrison's two best-known books are The Course of the Heart and Climbers, both of which fall squarely into the category of "general literary fiction".
Banks cheated, with his 'M'.
There've been others, too; notably Children of Men and the Handmaid's Tale. And going back a bit further, Gulliver's Travels (he goes to a different weird place every week, meets weird aliens, and makes some minor political points; that's basically just Star Trek TOS).
Curious what books you think should've potentially clinched it?
Ishiguro clearly doesn't care about that, which is fine, and I made peace with it, but as a result I'd actually be disappointed if somehow "Never Let Me Go" had won the Booker.