Sort:  

The implication of his post is that Winds of Winter will be published by July 2020 (when WorldCon occurs in New Zealand). However, that is not the last book. The final book is A Dream of Spring. He mentions them both on a post from May 20th: http://georgerrmartin.com/notablog/2019/05/20/an-ending/

He claims both books combined will total in the neighborhood of 3000 manuscript pages.

To be making a promise about when Winds of Winter will be done must mean that he is VERY close to being finished. I suspect he has significant portions of the final book done as well but we shall see. Hopefully it is not another decade before that one comes along.

Personally, I plan on avoiding the TV series altogether until I've read the final book. :)

I wonder if it’s the manuscript that he implies will be ready, or the actual book fresh out the press for all of us. I know nothing of book making but I assume there is quite a process before it’s actually published.

In some other post he mentioned he will not write the last book before he is done with the previous one. Though I would think he already has at least the outline in his mind.

I think it’s always better to read the books first, because then you can use your own imagination for the characters. When I read these, I of course already have the images in my head.

Whether it's just the manuscript or the finished product, at least the end appears to be in sight. It would take at least several months to go from manuscript to published book.

I know that some chapters he wrote for the previous book were moved to Winds of Winter. It wouldn't surprise me if at least some of the chapters he has written for Winds of Winter wind up in the final book instead. I agree it's better to read the books first and I've been avoiding the television series for that reason. I don't know if I can wait another 10 years for the last book though :).