What's Wrong with Greg Egan?

Or, more properly, what's wrong with US publishers?

Here's a guy who has written a pile of novels and short stories. Heck, he's won an award or three (Hugo, Locus and John W. Campbell Memorial, to be specific). His stories and novels are interesting...thought-provoking...they stretch your mind.

So why is it that his short story collection is only published in the US by a relatively small publisher? Why is it that his latest novel, Incandescence, is the only one of his works widely available in the US (his UK publisher published his whole backlist)?