Winston is not fully an appropriated "cog in the machine" in the novel's exposition. Throughout the novel, we see that there are parts of his life that actively embrace a world outside of Big Brother. His affair with Julia is one example.
Even when Winston is reeducated, he initially does not seem to be a completely changed person—as evident from the small doodles he does at the end while he is sitting at the Chestnut Tree Cafe. He also remembers his mother playing Snakes and Ladders with him. These "false memories" can be pushed aside, but they will always be with him. Winston might have been "changed," yet there is still a part of his consciousness, a small recess or corner of his being, that seems to remain untouched by Big Brother and the Party. However, by the very end of the novel, it is clear that Winston has wholly succumbed to his brainwashing as he looks up at a portrait of Big Brother with love.