I mean...they can play the other games. That's always an option. But I mean, the anime follows different rules anyways and is way more for merchandising then anything. They aren't just going to have only 400 pokemon show up in the series. I don't know, I don't see it as a big deal. To me just because certain Pokemon aren't in the current games, doesn't stop them from existing in the past games altogether. If I want to use Talonflame I can just start a new XY game.