That is just it though, there will always be those unexpected times when there is lots of smoke or lots of cars or stupid motion blur and useless bloom, silly lighting etc. Having it run fast enough so that there is a buffer before being unusable is incredibly handy. Sure, it is not going to happen all of the time but if your FPS goes into the can in the middle of a race...
Now, in the case of Racer, proper LOD handling or view distance reduction would likely be ok imo.
Also need to take into consideration other people's hardware. If something runs really badly (20FPS) on my medium system then how is it going to be for people with slightly lesser computers? Sure on new hardware something might have a min rate of 30, but most racer users do not actually use the very high end of the newest hardware.
*shrug*