Yep, OG GoT is dead. George RR Martin and D&D made sure of that. Truthfully, the show runners got the worse end of it anyway. Their Star Wars project was canned and then who even hears about them anymore? People hate them. I doubt they ever figured that they'd run out of source material when they started the show.

Meanwhile, George continues to refuse to finish his books (probably because he can't figure out how and people hated his ending) and instead works on other projects, people eat it all up, and he continues to collect his big paydays.