Look at what happened when DnD ravaged GoT, HBO contracted GRRM's oversight over HotD.

Thing is GRRM told DnD what to do when they ran out of material to adapt, though. Both parties spoke at length about their conversations. He fell behind with the books, forcing them to go to him, and he told them exactly how he planned on ending things. In fact, DnD said long before the finale that they forced him to explain everything about his plans just in case they were left in the dark. They did precisely what he told them to do.

Granted, they rushed shit because they wanted to move on, but it never rubbed me the right way that GRRM threw them under the bus after season 8 was panned. I also wouldn't say that HOTD is better than GOT. GOT was one of the best television shows in history until it wasn't, and while the first season of HOTD was very good, I don't think it touched the highs of GOT seasons 1-3.