I get it. It's been over ten years since the last book. People think that it'll never happen and the series will forever be unfinished.
However, that's clearly not going to happen.
This is his masterpiece. His legacy would be at stake if the series was never finished. It's taking far longer than he planned, but great works of art take time, especially when they're as complex as ASOIAF.
I hate to bring this up, but people always talk about him dying before finishing the series and his previous comments that he wouldn't let anybody finish the series if he died. I call BS to that. First, I believe he'll finish it himself and don't want to speculate on his health. Second, I don't believe his previous comments. Going back to his legacy, do you think that he wants his lasting legacy to be the man who not only didn't finish ASOIAF, but purposely allowed it to never be finished, meaning people have invested time and money into a unfinished story? Absolutely not. I guarantee he has plans if the worst happens and somebody will finish it.
Also, I'm pretty sure his publishers put in contingency plans in the event of his death. If George dies, they would have to stop selling the books because the series would never have a closure. No publisher would be happy to agree to this.
The series will be finished, either by Mr Martin himself or somebody else in the worst case scenario.