>>49954071If they included every single Pokémon in a single game, their models, textures, animations, cries and other assorted data would take up an entire Switch cart alone. This is why an online Stadium-style game is the only way to have every Pokémon in a single title moving forward.
Then it could download only the needed asset bundles as they are requested when a battle is loading and save them to the cache, unloading them afterward. Pretty sure that's what Pokémon Go does.