It helps when authors don't promise a complete series, with a predetermined finite number of books, and a promise of closure to a specific story arc.

Neuromancer was a standalone story when it first got published. Were there readers out there wanting more, when they got to the end of the book? Yes. Did anyone avoid reading it because there wasn't yet more? Of course not. William Gibson has followed the same pattern for every series he's written.

When Pattern Recognition and The Peripheral were first published, there was no promise that any further stories would follow. But people read them anyway, because they were complete stories already. All Gibson had to do was return to the setting and build new stories there, whenever he wanted. Revelation Space books sell just fine, because each one is a complete story in the setting.

Meanwhile, ongoing serial fiction thrives by never promising any kind of overarching narrative closure. Nobody avoided reading the first few Jack Reacher books because there was no end in sight to the series. Nobody skipped Charles Stross's Laundry Files because they knew there were more books coming.

Martin and Rothfuss made the mistake of promising a complete story, and then releasing it piecemeal. Tolkien actually wrote a complete story, and then publisher released it three volumes. Dan Simmons' Hyperion and Fall of Hyperion were both released the same year.

The moral is this: If you haven't written your ending, don't publish the beginning with a promise of closure. Just write each book as a complete story in itself, and build on what you've already written as you go.

And whatever you do, don't start writing Zeno's Closure, like Rothfuss did, where each successive episode makes half as much progress towards the conclusion as the previous episode.