The Hugos were not awarded until 1953, skipped 1954, and then restarted for good in 1955. They only had fiction categories for Best Novel and Best Short Fiction until 1966. In 1967 they added a Best Novelette category and in 1968 a Best Novella category, to match the Nebulas, which started in 1965.
This severely limits the number of award slots that were open throughout the whole of the Golden Age of sf and the beginning of the New Wave.
Locus Magazine has an amazing database of all the f&sf awards in the world. It’s broken down in all sorts of useful ways as well.
A quick check shows that Iain M. Banks has won 2 British SF Awards, 2 Italia, and 4 Kurd Laßwitz awards but no Hugos or Nebulas. Both awards tend to have an overwhelming bias toward American writers, both because the overwhelming majority of the voters are American and because for most of the history of the awards it was difficult to read non-American authors in their year of publication. People tended to catch up with them later.
China Miéville is in the same situation. He hasn’t exactly been ignored by the world. 2 Arthur C. Clarke Awards, 4 Locus Awards, 2 British Fantasy Awards, 1 Ignotus, 1 Imaginaire, 3 Kurd Laßwitz.
Clement’s award was a “Retro Hugo.” Because of the lack of early awards, a few Worldcons have created honorary award ballots for works that would have been eligible 50 years earlier, had there been a Hugo then. As honorary, 50-year-after-the-fact awards, they are fairly meaningless, going on later name recognition. And there’s only been three of them (in 1996, 2001, and 2004) so they’re pretty arbitrary as well.
Who hasn’t won one? That’s a good question. I don’t want to dig through all the lists to figure that out. Certainly, many good literary writers never even get nominated and most have no chance of winning, unless they break through to wider public awareness, like Kelly Link. In the same way, writers who pump out millions of words of military sf, like David Weber or David Drake or Eric Flint or S. M. Sterling, are equally unlikely to get a nod.
Most everyone in the middle has had some recognition, however. Occasionally it comes from a late award for not quite the best work, but that’s true of the Oscars as well. It’s a comfy, cozy, ghetto.