Why does it take George RR Martin so much longer to write Game of Thrones books now than 25 years ago?

 Have you forgotten how big A Song of Ice and Fire is? I think we forget that because the show wrapped all the loose ends up so quickly (and might I add unsatisfactorily to many), that it would take George RR Martin only slightly more time to wrap up the end of ASOIAF as quickly.

Let's be real. Martin began to fall behind when the show started production for HBO. Once Game of Thrones started shooting and Martin was writing and overseeing the show, there was little chance or incentive for Martin to wrap up The Winds of Winter while he was writing a show. And production on the next book was sidelined while the show took off.

I don't think Martin or HBO were expecting Game of Thrones to be as big a hit as it was. Because it was the biggest thing in Fantasy since Lord of the Rings was filmed. And when show kept getting more and more popular, there suddenly grew an urgency for the books to begin wrapping up. And by the time Season 4 ended, Martin returned exclusively to work on TWOW. And by the end of Season 5, the show officially outran the books. So, while the show began to work with broad outlines and ideas, they were essentially on their own. It didn't help that the dunces in charge were only interested in making three more seasons, instead of the 5 or 6 George envisioned. But, back to George.

Think about how many active storylines need to be continued and wrapped up. We're currently following separate storylines at The Wall, at Winterfell, in the Vale, in Braavos, in Oldtown, in the Dothraki Sea, in Meereen, in the Stormlands, in Dorne, in the Riverlands, Beyond the Wall, at Skagos, in the Iron Islands, in Volantis, and in King's Landing, not to mention what can still happen at the Neck, or what will transpire in the Reach with Euron wreaking havoc there, and also not speaking about the Others and the massacre at Hardhome. And with all these storylines to follow, an incompetent writer would simply have death left and right, but George isn't a fool nor is he a lazy man. George will have to wrap up each story intricately and properly, lest he face the same backlash HBO and the Dunces got. Well over two dozen characters will need to have their stories and plots not only end or continue properly, but also keep them focused on what we're all expecting will be the final contenders for the Iron Throne standing: Dany and Cersei. That means Stannis's bid for the throne will need to draw to a finish, as will Sansa and Littlefinger's Vale plans, Arya's faceless man training, Jaime will have to confront Lady Stoneheart, the Faith Militant will need to be destroyed, Aegon VI or Faegon will need to come to the forefront, Bran's training in the North will need to conclude. Adding to this, Jon will need to be revived, Davos needs to find Rickon, Dany will need to get back to Meereen to meet Tyrion and destroy her enemies, while also dealing with the Dothraki Khals.

So, yeah, George RR Martin can get the benefit of the doubt when it comes to working on a book that will essentially deal with roughly 1 1/2 seasons worth of story, especially since A Storm of Swords was technically comprised of events from Season 2 to Season 5. Do we really want another unsatisfying ending to something we love just to have it out quicker?