Allegedly ran out of his material.

For example. The first Harry Potter movie came out in 2001, the final Harry Potter book came out in 2007. JK Rowling told Alan Rickman Snapes character arc before filming the first movie and had him promise to keep it secret which lead to some arguments with directors with Rickman because he knew Snapes motivations but was sworn to secrecy.

I don’t think the HBO writers had nothing to go by. I think they were given an outline to the final 2 books but the show runners at the time had a Disney Star Wars offer and they needed this wrapped up. So they combined 2 unfinished books into 2 shorter seasons.

And we all saw how that turned out

Allegedly ran out of his material.

For example. The first Harry Potter movie came out in 2001, the final Harry Potter book came out in 2007. JK Rowling told Alan Rickman Snapes character arc before filming the first movie and had him promise to keep it secret which lead to some arguments with directors with Rickman because he knew Snapes motivations but was sworn to secrecy.

I don’t think the HBO writers had nothing to go by. I think they were given an outline to the final 2 books but the show runners at the time had a Disney Star Wars offer and they needed this wrapped up. So they combined to unfinished books into 2 shorter seasons.

And we all saw how that turned out