It is a team game. The pros play it as a team and if you ask any GM, it is a team game. Your definition of team game is a little broken in that sense. If you can’t win a game on your own then it is a team game. If you need to work together to accomplish something it is a team game. Maybe in the low elos it is different. I know that because I’ve been playing in them, but when playing the game in it’s “intended manner” it is heavily team based.