Unreal Tournament is given as an example of an old game that never died. But I've tried to play it with a group of friends, and we found it too buggy. Unmaintained games will stop working eventually.

First there was a brightness problem; the game was too dark on multiple computers to be playable. Eventually we found a patch somewhere for that. Next we noticed that the player hosting the game could run much faster than the others. We gave up after that.