I think the curriculum will have to be revised to correct achievement disparities with other nations. On a par at 4th grade, ours have fallen behind by 8th grade. That's mostly because seventh and eight grades are black holes that do not introduce new skills here. Improving the relevance and rigor of 7-12 would be the best way to lower college costs, because, once again, young people could go into the workplace qualified.
The interesting comparison is that many countries other than the US don't have their kids start school until age 7 or 8. Norway is one example of this.
So, at 4th grade, our kids have been in school for 4 or 5 years(counting kindergarten), and other nations' kids have been in their schools only 2 years - yet their kids have learned as much as ours.
Is that because our kids are that much less intelligent (lower IQ)? No, I am sure it is a direct result of the curriculum used.
If you want a direct comparison you can do at home, pick up the first book of Singapore's math curriculum, then look at our first grade math curriculum. It's a difference between night and day. The Singapore math books are used in classrooms with 45 or more kids per class, and these kids, by 8th grade, vastly outstrip ours in class sizes of 25 or less.
In places like Indonesia and Singapore, parents have, on average, considerably less in terms of family resources and education levels than average US parents. Additionally, we've spent more than double the amount on our kids' education than they have.
It's the curriculum, folks. IQ is just the quality of the slate brought to the table.