Game of Thrones as a TV show has been an incredible experience for both fans of the books and first-timers with no previous experience with George R. R. Martin's A Song of Ice and Fire. The book saga has been in the making for a long time, with the very first novel being published in August 1996, and the sixth out of seven, Winds of Winter, is the one that's taking Martin the longest to finish. In fact, he recently declared he's 3/4ths of the way to the finish line for Winds of Winter, which is possibly tied to many factors, such as Martin's involvement in making Elden Ring and the Thrones spinoff show House of the Dragon, or the fact that the TV show's ending was generally believed to be a disappointment.
There's a strong possibility that Martin is indeed taking more time to change the course of events he had planned for A Song of Ice and Fire in order to make the books stand out from the show, which makes sense based on the latter's reception toward the end. While some fans are not happy about the books taking so long to come out, it's safe to assume they won't face the same problem with rushed plot points or characters not having enough space for their stories to be told. However, this also means that a Game of Thrones RPG video game meant to span the events of Martin's seven books could take over twenty years.
Why A Game of Thrones RPG Based on The Books Will Take Years to Make
A Dance with Dragons, the fifth book in the A Song of Ice and Fire saga, was released all the way back in July 2011, which means it's already been over 11 years since Martin's last entry. The longest gap that occurred between two of Martin's books' publication dates before Winds of Winter was six years, which was from 2005 to 2011, with the former being the year A Feast for Crows came out.
If Winds of Winter takes Martin another year or two just to finish writing it, it would come later than that due to the editorialization process, possibly moving the release date to sometime in 2025 at the earliest. While there is no estimate on how long it will take Martin to finish the seventh book, solely basing one's hypothesis on the fact that Winds of Winter took this long leads to the conclusion that it could easily be several years just to write it.
As such, A Dream of Spring could be done in terms of writing after another ten years since Winds of Winter, and then again there would be the whole editorialization process before it sees the light of day. If that's the case, then a Game of Thrones video game spanning the entirety of A Song of Ice and Fire would need to start development only after the book series is done and out, which is already likely to be in fifteen years from now. Additionally, A Song of Ice and Fire is an even larger source material than the Game of Thrones series.
In fact, several characters and story arcs Martin wrote in the book saga never made it to the screen, such as Lady Stoneheart, a character that becomes a vital part of the storyline of characters including Jaime Lannister, Brienne of Tarth, and Podrick Payne. Similarly, Game of Thrones' Daenerys never got to meet Young Griff, a character that seems to be key in her arc in the books, possibly shaping her ending differently from the TV show. Ultimately, a Game of Thrones RPG would be a polarizing experience for long-time fans of the series, but the overall amount of time needed to play it could very well be over two decades from now.