> Instead of wasting at home or on the streets, we could send them to the therapy they need.
I'm not advocating against this. But keeping their education timeline somewhat on track is highly preferrable in my view (inserting "fixed delinquents" into classes of younger children seems very undesirable to me).
> And maybe subsidizing them is the cheapest outcome: better we give them a small amount of money and get them to leave us alone, than spend more trying and failing to get them into schools, the workforce, or prison.
I honestly don't see how this could ever apply.
You have basically an average >$200k investment from the parents alone, plus all the direct/indirect subsidies starting with day care. Between low-wage working adult and "worthless person" there is at least a $50k/year swing in expected value to society every year they work, too.
Even if your success rate of "fixing" child delinquents is laughably low (say 15%), and costs you like $100k per attempt it is easily worth it; its not even close.