A lot has to do with it being rewatched and rediscovered like someone else here said. I think it was restored since 2012 and it is now a lot easier to watch online than it was 10 years ago. Another factor that I think contributed greatly is the fact that people wanted to have diverse ballots (I don’t necessarily mean diverse as in from different countries, gender, and race, but more like I think most people wouldn’t like to have six Hitchcock films for example, even if they love them, because they would be using over half of their votes in basically the same thing when they can spread it among the various things they think are important to represent in a greatest films list, to some it would be putting a film from each of the greatest directors, the best film from each genre, their favorite film from their country, and to some represent women filmmakers who are still incredibly underrepresented when we discuss film history as a whole).

Besides, if you remove the feminist themes (which I don’t know why you would since it’s an integral part of the film, but still). It is still an incredible achievement and an amazing movie that is worthy of being considered number one.