I completely agree with this. I actually think LFS may have a more consistent active number of drivers then any other sim. Everyday during prime time hours it is at 1200 -1300 or more. In sim racing terms, because of a small community, that is huge. I will tell you why the other current titles don't or don't yet.
rFactor is just too much trouble. The mods need computer assisted organization.
iRacing is just too expensive for a large portion of the sim community as a whole. But, it is an excellent simulation and I have just purchased a year and my D-Class content packages. But, I see less drivers online during prime time then in LFS. It is a hell a lot of fun though.
GTR is cool. And I can't put my finger on it, but it is just wrong some how. Maybe it is the ice effect of the road.
-Jay