Actually, that's not completely facetious. What if the payment structure was changed from being based on the number of inmates, to a flat fee, with a cap on how

Actually, that's not completely facetious. What if the payment structure was changed from being based on the number of inmates, to a flat fee, with a cap on how many prisoners a single company could guard (going over that requires housing by the state). Then the company is incentivized to lower the number of people being put in jail rather than raise it; you start seeing lobbying for decriminalization of non-violent offenses, since that leads to fewer prisoners, less cost, same revenue, thus increased profits.