I decided to take the advice of others and add a cap to the games. I added the following to the rules:

There will be a cap of 40 rounds for each game. If the cap is reached, all players still alive will split the available points (ie. 2 players left - both get 8 points; 3 players left - each gets 6 1/3 points; 4 players left - each gets 5 points).

Still looking for 6 more players.