There is no one endgame - where the game ends. It never ends! The phrase is used a lot, but never defined for this game. On any world there are players whose own end of game on that world is to obtain a 1st place badge. Some have an end of game target of getting a badge and then intend to leave. Some see the end of game as nothing more than getting everyone a badge, others the opposite ie preventing anyone but the main 1st badge alliance and it's wing getting a badge. There is no one end of game. With 50 000 on a world there could be 50 000 end of games. For some it will be when the money runs out, or when the wife/husband/partner realises how much time/money the game is consuming.
You can have your own end of game at any time, by leaving a particular world. This is a king of the hill war game, if you don't like it then don't play it and don't spend money on it.
The only End of Game that is certain is that when EA decide it costs more to maintain the servers than they receive in revenue it is time to pull the plug!