Because sim racing is a niche hobby, so it's hard for any regular sim to get the number of regular racers required for matchmaking to work effectively. I know people keep pointing towards iRacing, but the fact is that that sim charges a monthly fee which pays for all this "extra" stuff. Most other sims don't so they can't provide the same level of support. That's where communities like RD come in, to provide quality racing for all levels without having to worry about wreckers.CatsAreTheWorstDogs: A lot of people does allready complain about Racerooms Ranked servers because of lousy participation.
Sure but at least for the major series it's very cool to be able to find people to race with. For example in iRacing Skip Barber is always filled with full of racers