The fact of the matter is this:
More people play rF because it's easy. You can get in and use all the aids and crap to make you think that you actually have some skill. When I played it (briefly), it was an un-modded version and the environment textures were horrible. The Dx9 shading and reflections were okay on the cars, but when you're half a lap in front all the time you don't really notice them.
LFS requires a lot of time and dedication to get it right. You need to tweak the setups to suit your driving. Even with the basic aids we have, it's still very easy to send the rear end wide on corner exit or lock the wheels under braking and fly off the track.
And with people being the short attention-span beings they are, they don't want to put in the practice. They want instant gratification, which a proper sim can't give. Do people expect to get into a real race car and set WRs on their 2nd or 3rd lap? No, it takes years of practice.
But anything worth it's salt is worth waiting for. Once LFS is actually released it will get the recognition it deserves. Until then, we need to just chill and enjoy what we have before it's ruined by a huge influx of "t3h m0r0nz"