I feel like I am on a bandwagon having read Wool, but bandwagons become bandwagons because they have something that resonates with people.
In the Wool series, Hugh Howey has created something he couldn't have foreseen. Amongst other things he has made readers care about his characters, imagine a believable future and he's kept them wanting for more.
I don't know if it was his original strategy, but I am glad that Wool started out as a novella. If you can grab your audience, engage their emotions and curiosity in a short form, you're probably a pretty good writer. Either that or your story has fired the what-if chemical in the readers brain, as Isaac Asimov did in the Foundation series, Frank Herbert did in the Dune series, Virginia Andrews did in much of her writing. These three writers created such a legacy, there are still books being published as prequels, sequels and spin-offs of their original works.
I'm not comparing the content of Wool to these others, but it already has the potential to grow beyond the scope and grasp of its creator. This is something most writers dream of.