>>50431611I've always felt that's because, while Gamefreak and Nintendo are well aware of Gardevoir's popularity, they're also well aware of WHY a large chunk of the fanbase likes it so much. Turning Gardevoir into more of a mascot character also brings more public awareness to it's status as Most Waifuable pokemon, and they probably don't really want that out in the open. So while Gardevoir actually gets a lot of cameos and appearances, in the games, spin-offs, and anime, it's never really used as a marketing tool directly like Lucario or Pikachu.
