our kids in American society

In Chapter 1 of “Our Kids” Robert Putnam talks a lot about opportunity, and how that has changed, and how it relates to inequality. What do you think “Opportunity” means? He also cites surveys showing that 95% of Americans believe in the idea of “equal opportunity.”
This is the idea that everyone should start out with equal chances in life, yet in the US, it seems this is not the case that we have equal opportunity. Why do you think this is?