Sure, plenty of kids and teens would not get educated, but they're probably not get anything now either. You can't make a student that won't learn educated anymore than you can make a morbidly obese person who refuses to eat right healthy. Sometimes society is better off with such people being allowed to make themselves into warnings for others.
Setting aside the sheer depravity of this argument, we have ample historical context for what happens when society cuts off the neediest. France, Haiti, Cuba, China, Russia, Algeria, Egypt, India, Scotland, The Phillipines, Mexico--just to name a few places where social and political inequality have driven massive, bloody revolts.
Wealth and political power calcify with the already wealthy and powerful. The middle and working classes slowly lose what wealth they have through attrition. Poverty becomes a virtually inescapable sink of destitution. Eventually, enough people end up having quite literally nothing to lose that you get vicious, deadly, destructive revolutions that take generations to recover from.
If you insist on taking a "pragmatic" view of not even bothering to -try- to improve the lives of the impoverished, try to at least understand the historical ramifications of what you're arguing for.