The elephant in the room regarding public school education -
1 in 5 children in the US is living in poverty:
http://www.huffingtonpost.com/2012/12/18/child-poverty-2011_n_2323383.html
I would venture to guess that that means a hell of a lot more kids are living in families where both parents are working multiple part time jobs.
Many of these kids are not encultured to try to succeed at school; often times they have no idea what skills are needed to succeed at school.
Figure a class of 30 first graders, 6 of whom need special attention to learn to read and do simple arithmetic. Now, let's get more realistic, and note that residential areas in the US tend to be segregated economically. Maybe half or more of those 30 kids needs one-on-one on a regular basis.
When school starts this fall, take a look at the kindergartners and first graders - they're excited and interested. Take a look at the older kids. Only two or three years older, and already they have dropped out even if they are physically present.