Actually it does. By almost any measure of achievement, folks sort themselves out into a bell-curve, with a few super-high and super-low achievers and a bunch of folks in the middle.
The reason the left wants to eliminate class rankings is that Black and Hispanic kids do worse, on average, than do Asian, Jewish and White kids. In the leftist mind, you have to eliminate anything that will distinguish because any distinction that does not favor Blacks and Hispanics is, by definition, racist. So you eliminate class rankings. You argue that GPA is sufficient, But the next step is GPA becomes meaningless because everybody gets an A--it's called grade inflation and it's already happening.
It's unfair to the kids who work hard (of any race or creed) because they aren't allowed to stand out from the pack.
The newest trend developing is the standards based report card.
4-exceeds standards, 3-meets standards, 2-partially meets standards, 1-does not meet standards, 0-well below standard...Just a politically correct method of not mentioning the GPA of students of ethnically diverse backgrounds.