I personally don't think that it would be such a bad idea. Compared to the number of students that don't really actually do anything with their vacation, the number of students that get part time jobs, help their parents, or do vacation homework is relatively low.
In other countries they have school even on saturdays and much longer hours than we do and they are prospering, so I don't really think that the number of highschool drop outs will increase.
I do agree that we should be learning more life skill courses like how to do taxes, balance a check book, and learning how to save money and not spending it the second we get it. Those kind of things would better the economy and helps millions of graduating students.
All in all, I just think we should all be thankful for the school we have. Many students and parents seem to take it for granted. In many parts of the world, kids can only DREAM of going to school and really wish they could. So we should be more thankful for what we have rather than being nit-picky about them.