I'm well aware of the Unicor program wherein corporations the likes of Bank of America and Victoria's Secret (among many others) contract for prison laborers and get them at a reduced rate. Actually, Unicor jobs pay about $1/hour and are the jobs inmates hope to get.
Where I was, we didn't work for corporations. We simply did all the work it took to run a prison. And for pennies per hour (kitchen, suicide watch were my jobs). We weren't a private prison.
But I agree with what you're saying completely. Most guys where I was didn't really need to be locked up as they weren't going to hurt anybody. And private prisons are a really bad idea. It's like running a hotel. "Keep those rooms filled so the place turns a profit."
Ironic that if Trump loses, he might end up in one. Nobody is more deserving. Check out my piece on having Paul Manafort as a celly.
https://medium.com/doing-time/blowing-his-own-horn-93968c1ec8cb