If you think about it, isn't it just a massive "fuck you" that Ash Ketchum, the Champion of Alola, the man representing their region to the international community, doesn't use a single Alolan mon? That he could so very easily give his partner its Alolan form but staunchly refuses for no real reason? To add injury to insult he's not even a citizen like in the games, he's just some kid who vacationed there and walked away their king. This is basically the Pokemon equivalent of Obama's birth certificate.