It never happens.
The only way for a game to "die" is for the developers to kill the game itself.
this could be done via removal of fan favourite features
or lack of updates.
staleness
you could say lack of updates but at a point it doesn’t even help. People only stay attracted to a game for so long before moving on and having fun playing something else. We all are just playing for fun so in the end majority of us don’t have a attention span to play a game long enough to be really good. Or by that time we get bored and switch games circle of Gaming