You have just described the current state of affairs in the USA.
The war on drugs produces the raw materials (IE, people to put through the system).
The harvesters (the police) get paid for spotting, cutting down and initial rough processing of the raw materials.
The courts (attorneys and judges) do the separating and grading of the rough cut materials.
City and County lockup (jails) do the fine detailing to turn graded rough cut materials into finished products (real, full fledged prisoners)
They then and sell them to businesses (State and Federal prisons) that need the finished products (slave labor prisoners). Call it a business to business transaction.
State and Federal prisons then use their purchased products (slave labor prisoners) in their various industries (manufacturing of electronics, weapons components for the defense industry, you name it).
After the finished product is used up (released from prison), they are recycled and put back through the process.