Any site that tracks the "score" of your contributions and then makes your "score" visible on most pages is going to be about winnings whether that's the stated goal or not. That is a textbook way to gamify things.
Obviously this applies more to comments than to submissions but the comments are a large part of the user experience here so whether HN is "based on this premise of winning" boils down to a question of the importance of the comment section.
Dopamine feedback from imaginary points, and validation from mostly like minded peers makes users keep coming back to this website. Otherwise user retention would non-existent.
Obviously this applies more to comments than to submissions but the comments are a large part of the user experience here so whether HN is "based on this premise of winning" boils down to a question of the importance of the comment section.