I guess this relates to one of the central themes of the novel. I find it incredible how when reading this novel we as readers have our hopes raised enough to make us think that his rebellion will actually work, only to have them completely and irrevocably crushed. On reflection, in such a world, I would suggest that there is nothing that an individual such as Wilson can actually do. Any attempts he has to rebel seem to be actually given to him so that they are used against him later and used to convict him. He lives in a world of total surveillance which can only end by outside force or pressure or the government itself imploding. Wilson and Julia´s rebellions are futile and, above all, permitted. Which doesn´t make them rebellions at all.
I think it's actually one in the same-- Winston is not a hero but a truly average man, and what average man can defeat the massive totalitarianism of Big Brother? Winston is just being realistic.
At the same time, on a personal level, his rebellion succeeds. He is able to think freely and even act on it, even though it is all in vain. That small, internal revolt is ultimately worth dying for, even though it accomplishes nothing for anyone else. A brief moment of freedom for an average man has value.
In a society like this where even Parsons, a perfect citizen is arrested by the Thought Police, I think it's almost a guarantee that Winston would have met his end. I think it is an inevitability for almost all citizens that are from Winston's generation- anyone who was alive before the Parties formed because these are the people in society who are no absolutely "pure". These are the people who are in danger of remembering how the world used to be and are in danger of remembering that history is not something that's fluid.
Ah, the ultimate question. Similar to Macbeth - would he have sought the power if the seed had not been planted by the witches.?
While not attributing my answer to fate, I think Winston would have ended up in the same place. He was too weak a character to begin with. His "rebellion" is lacking in strength. He wants to challenge Big Brother, but he doesn't exactly know how to do it. He has to be lead along the path of resistance, by O'Brien and Julia and Goldstein. He fears Goldstein initially, even though he supports the cause. Winston does not have the strength of his beliefs and despite his desires, he is too mired in the society to successfully break free.