But, then again, California is not the best example here, as California cost per prisoner is way, way above national average (despite being below national average 30 years ago). California has pumped its cost per prisoner through the roof, which is then used to justify reduction of prison population, as too expensive. Either way, California is not known to care much for its fiduciary duty to its taxpayers.

In Arizona, private prisons are still cheaper, though the disparity there is only 1.25x, not 3x. Also, state prisons in Arizona are cheaper than private prisons in California. State prisons in California are 5x more expensive than private prisons in Arizona. If California contracted Arizona private prisons and shipped its prisoners there, it could save >$10B annually, more than 5% of its entire budget, which could then be used on schools, infrastructure, and public safety. Of course, this 80% reduction in prison spending will never happen, prisons being expensive is too politically convenient.