Gran Turismo was the reason I got a PS2, and Forza was the reason I got an Xbox 360. I already played racing games on PC with a wheel and could have stuck with that if there was anything like GT/Forza on Windows.
I don't regret the chance to play other PS2/360-exclusive racing games, though.
I don't regret the chance to play other PS2/360-exclusive racing games, though.