Another easy way of improving the school system would be to expell the students who have no hope of passing year 12 when they are 14 and make them work at McDonald's.
How would that be decided fairly? How would it avoid picking up a huge number of disadvantaged students? Would a better solution be to put under achieving students in different classes?
I'm guessing you wouldn't want to actually force them all to work at McDonald's and that is just an example.