Because, you see, there are no more recurring characters in Kirby aside from the trio we already have. Galacta Knight? Who’s that? Bandana Dee? He only appeared in a minor minigame in Super Star. What’s that? He appeared in many Kirby games in recent years? What ever could you mean? There haven’t even been any Kirby games in recent years, you silly goose! Everyone knows that the Kirby series ended after Kirby Air Ride! I mean, I guess there’s the post-AR Kirby games, but those aren’t really true Kirby games since Sakurai wasn’t involved in them and all. Never mind that they were some of the best games in the series, nooooo, they were made after Masahiro’s departure, therefore, they “don’t count!”

Zelda hasn't had any newcomers since Brawl though.