The sad reality is we are already spending far more than we did in trying to send people to the moon on 'closing the achievement gap' but getting no where in those attempts.  Why?  In part because we have damned significant parts of the population with low expectations.  In part because MONEY isn't the issue desire and values are. When your value isn't getting your child an education but getting them free daycare and food so you can go on partying it shows in the student.  Books are important but if they sit on a shelf and gather dust that does the student no good. 

What we have proven with spending loads of money is that spending loads of money does not fix the problem.  There are no silver bullets because the reasons for the gaps are as varied as the kids that are struggling.  The sad truth is if a child has any one teacher that is bad in the first 3 years of school it sets them back much further than having a bad teacher later in their schooling regardless of parental involvement.