I feel like it's pointless to say "good on her for getting that hit" or "bad on you for not hearing the potential." I think it's luck in the sense that Rihanna's voice was the best for the song and the two things combined propelled it to be a hit. It probably wouldn't have been a big hit if another artist had sung it. Maybe whoever turned it down knew it wouldn't be that good with their vocals on it. Who knows. And who's to say some flop songs wouldn't have been massive hits if someone else had put their spin on it? Just because an artist turns down a song and then it turns into a hit for someone else doesn't mean they should have kept the song. It could easily tank either way.