I agree with this, however, I don't think you are giving it enough of a chance. During my play with the beta, my highest finished was around 8 or 9, which i felt was pretty respectable considering i was using a controller and hadn't touched a racing game in over a year. My BIGGER gripe however, was not the speed of the other players, but their incessant need to knock me off the road. I won't mention specifics, but there did seem to be a certain demographic that was highly prone to this style of racing. The point to this is that my SR went from a B to a D - all because I kept getting slammed into from behind and pushed off the road.
I, personally, would rather finish dead last every race than spend half the race in the dirt and up against the wall. I have to believe (and hope) that once this game actually releases and there is a month or two of racing going on, these sort of things will 'weed' themselves out, and you will have an opportunity to win. As others have stated, winning isn't everything, and giving up after a 4-day demo seems to really be jumping the gun.