You are missing the point.
Many people strive for as much realism in their "games", not only in racing games, but also in flight sims etc etc.
To many people, realism is the over riding factor in choosing which sim to play, arcade games have their place, heck I enjoy playing Midnight Club LA.
Not everyone can afford to race IRL, which is why they strive for as much realism as possible from a racing sim, and iR is that sim, it's as close as you can get to real life racing on a PC, for now.