I don't see the value in going to the trouble of making a real track, if (almost) nobody has heard of it. Just because it's real doesn't make it better or more fun to drive, and in many ways you are just limiting and restricting yourself. I actually think the same goes for the cars too. Is RAC any more fun than a fictional car would have been?
Ok you get a bit of publicity, but the level of that is purely dependant on how well known the car/track itself is (or will be).
If they ever add a real track, it HAS to be one people know instantly and want LFS because it's there, otherwise what's the point? I doubt many people look at the LFS website and think "hmm, I'll just do some research on these tracks I've never heard of. If none of them are real I won't be buying this game, that's for sure."