In Pokémon, especially the games, the player defeats the current champ. After defeating him, the team is registered and the player start... at home. Then the player can roam the country and even defeat the old champ as often as he likes. And he still is in the same place, in the champ room.
So, is there a in-universe explanantion why the player is allowed to roam freely, while the old champ has to stay put?