As much as I love Pokemon. This is one of the reasons why I like the Yugioh animes over the Pokemon anime. I mean every protagonist in every series won their respective tournaments. Even Yuma, a protagonist who lost a lot of duels still managed to win his tournament. Does the Pokemon company believe that if Ash wins a league they need to end the series? This isn't Gilligan's Island. You can still tell stories of the hero even after they won a major tournament.

Neither May nor Dawn has ever won a Grand Contest either.

Seems that main characters are doomed to always fail… at least, on screen. (No telling what May and Dawn have managed to do offscreen since they left) And since Serena will most likely continue with Ash, she's continue to lose.