All games die, regardless of how many people played it.
Battlezone II, for instance. Released in 1999, still has about 10-20 players on each day. However, it's pretty much never mentioned online, on forums, or the like. Same for the original one.
You could also consider Tribes (2 and Vengeance, unsure about Starsiege: Tribes) dead, it's never mentioned online but usually has 40-50 people online during the day, versus hundreds in 2002-2003.
Chances are that Badspot will shut the down the master server when the player number drops below 20, and the game will then connect to the Torque master server. (and I think you can already switch to the master server by messing with configuration files, but there's no point, since the torque servers suck.)
