Author means it is an conceptual advantage for historians of social history to accept an analogy between their research endeavour and interpretation of the past in the terms of the game. Not only the rules of the game as such are 'timeless', but also the capability to reach a broader consensus regarding the rules 'how to play'.
In this analogy a proficient player does not always have to win, yet he/she is able to manage not to be out of the game.