Specious. There are plenty of obstacles preventing them. Crime, drugs, poverty, lack of family/parental support, bias in the criminal justice system, a lack of direction, poor/inappropriate role models, poor influence from cultural values.
12 year-olds who are thrown on the corner to make more cash selling drugs in a day than their mom makes in a week often don't know better, or more importantly, don't believe they have any other options. because they don't see many around them doing the right things and succeeding at it. Instead they're heavily influenced by cash thrown to them by adults who know those kids will be in and out of processing because they are juveniles.
Through sports (which is just one way, mind you) these kids can be made to believe they have other options.
This topic is far more complex than "they should just go to school and study". We know they have options, and obviously a harder road than most, but if they don't believe it, because they don't see it, none of that matters.
And we're talking about kids. They need to be raised, educated, guided, shown the right way. It's unrealistic to expect the majority of them to figure out the right way on their own, when they've grown up around so much negativity.