There's just a lot of randomness in what gets attention/traction off /newest. That's why HN doesn't try to prevent reposts of stories that haven't had significant attention yet.
It sucks when you're earlier and don't 'win', but it evens out in the long run if you post lots of good stories, since sometimes the lottery works in your favor. One of these years we'll get around to implementing karma-sharing to spread credit across multiple submitters.