try doing some logic, if you would shoot an arrow to a car that is driving, do you think that the car will still be there when you shot the arrow? no, because it has moved sideways from where you're looking.
In real life you would compensate by aiming more to the right/left offcourse, but somehow, that is left out of the game. too bad because the higher your skills is, the more it ought to be compensated
I hope this makes sense