LFS attracts at first the "non-conservative" Simracer, cause it came from a total different point of view. Ask any GPL freak, Nascar fan or whatever, to race you in the GTi. He wont.
The typical simmers want sims of fast racing cars, usually not available to buy for yourself. That's also the reason, why this genre has usually an older age, cause at the same time a Sim gets really really difficult, when simulating the actual high speed motorsport, and as a beginner you have to start with all the helps on, to get it going.
In LFS you start the GTi as n00b, and can manage a real simulated car on the track. From that point comes the confidence in being able to master a Sim.
To put it to one sentence: Why there are more LFS only guys, rocking in other Sims, than the other way round? Where are the team redliners, hackkmanns etc. that pwn (to stay with the 1337-speak
) every Nascar/GPL race? Why is there a column about the chat behaviour on LFS-servers in A.S.S.? Cause LFS wakens them up, shakes up the sim-scene, opens it to new parts of the market, enters the "eSport-scene", going side by side with CS, WC3 etc. Actually LFS has afaik the most prizes in online simracing available atm.
And that's the main reasons new people come to it, that's maybe also the reason some of "us" are fanatics when it comes to advertising the "own" Sim. Because LFS goes new ways, compared to the old and conservative ones of the simracing scene since years.