Orwell not only foresaw the communist victory (he saw that victory everywhere, in fact) but also foresaw that Russia and China would not form a monolithic bloc but would be deadly enemies.
There, his own experience as a Leftist sectarian may have helped him. He had no Rightist superstitions concerning Leftists as unified and indistinguishable villains. He knew they would fight each other as fiercely over the most trifling points of doctrine as would the most pious of Christians.

:side-eye-1: