Our backyard tetherball pole (left) was replaced with a non-competitive variant (right). “It was just all about winning or losing” one eight-yeard old girl told me.
As you can see, the new one does not specify a “win” state signalling that the game is simply about keeping the ball going. In this sense, it is not goal-less but actually cooperative as the preferred state of the game for the two players is one and the same.
Of course, this doesn’t solve the enigma of why the rackets are always missing.