if the alternative is to have them stay at home and just hang out with others who aren't motivated, i'd rather have them at school. think of the carnage THAT would potentially cause. and a shot in the dark here, but i'm guessing most of these kids are probably not ready to enter the work force. that spells a TON of trouble.
some kids are late bloomers. you have to give them that chance at self-discovery, even if it's not the majority of kids in this situation.
i wish all high schools would teach more life skills classes, like how to grocery shop, maintain a bank account, read food labels, fill out a job application, etc. Also, have those kids take aptitude tests to see where their interests really lie and start sending them down that path. we need as many mechanics as we do business people.