Becuase this game is based on level not xp(experience),So there are many players of same level.If you want to be top player in game you are in top league and you can't play this game individually so it is impossible.But there can be some player who have top quality of players but they can't be ranked no 1 as there are no club rankings based on individual data,but still I think there must be ranking bases on totals wins or goals per season.