Here is my little say in this thread.
There was this game released in 2003 called Nascar Racing 2003 Season (AKA NR2003 (youtube it))
It is still very actively played around the world (and me). The company that made the game doesn't even exist any more.
There is a free demo that you can get on the net, just do a quick search.
The thing I am trying to say is,
Just because a game is very old, doesn't mean that it is getting less people playing it. NR2003 is actually a couple of months older than LFS. (The first official release.)
Edit: It is also very alive because It is partially open source and there have been a lot of mods updating and making new tracks and cars made by the general public.