There are a lot of stakeholders that invest in prisons.
The more people are incarceration, the more the income that stakeholders get. This article relates to the topic in that it provides the historical view of the prison system. The author has also written a lot of articles about inequities in the prison system
Reiman, J., & Leighton, P., (2015). The rich get richer, and the poor get prison: Ideology, class, and criminal justice. Routledge.