From even before we are born, social rank plays a huge part in how successful we can be. When our country is in a more socially generous mood, we talk about leveling the playing field or creating equal opportunity, but these are usually half-ass measures that create more bureaucracy and provide little gain (No child left behind) or if there is a successful program (Headstart) it is gutted and restricted to do the least possible good.

Now imagine these inequities continuing on through college. The slope increases exponetially. If a family cannot afford a few hundred dollars a year in dental care then there is no possible way for it to afford $20,000 in college tuition. College actually becomes even more difficult for the middle class, who lose out on pell grants because of income limits. For the wealthy, admissions to top colleges are easier because colleges are more likely to admit a less capable student with the ability to pay full tuition than a more capable student who requires a scholarship.
I think (or at least I hope) that we can all agree that what class a child is born into is not the child's responsibility but is rather the result of luck. A fetus does not have the ability to schedule prenatal care, a newborn cannot breastfeed itself, and a kindergartner can't pick which school district to live in. Most importantly, leaving all ideas of religion or destiny out of it (because this is social science, not Sunday school) children don't get to pick their parents. Their lot in life is entirely a matter of chance.
There is a point when an individual needs to take responsibility for their own lot in life as an adult, but we generally thrust that responsibility onto to people just when the slope gets steepest (college) after having done little to nothing to give the majority the tools to change their lot. There are a number of changes we could make to even the playing field. We could start with universal healthcare, paid maternity leave so all mothers could breastfeed their children for the recommended period, increased daycare standards and subsidies, making public universities free, providing more tutoring assitance in primary education, etc. But instead we give more tax breaks and increase military spending.
Actually, the tax breaks and military spending make sense if the idea is to keep the playing filed uneven. It gives more money to those who don't need help and it creates an option for those at the bottom that those at the top never take- joining the military for college money.