Game of Thrones author George RR Martin writes all his novels on an old MS-DOS machine, not connected to the internet, and he uses WordStar 4.0. [1]
Maybe should focus on someone like Stephen King or Brandon Sanderson who actually pump out writing.
But what does he use to not write them?
One thing I have noticed about S-tier writers is that most of them have an established routine and stick to it. Why risk breaking something that works? With an established routine, you settle into it, and muscle memory puts you into writing mode. Start mucking with the routine, and that is how you get writer’s block.