NORTH AMERICAN STONE AGE
why does a 1990 and a 2007 chev car still get the same mpg? ....how long do they need to make a more fuel efficent car? .....
In a nut shell, the newer cars are probably bigger, has more equipment which ends up adding up in terms of weight and more horsepower and torque. I am not sure which models/platform you used to make the comparison