And communism works great as long as the bad guys never get power either.

You'd have to corrupt a fuck ton of people to abuse a for-profit prison system. From cops, to sheriffs, to DAs, to Judges, to Juries, to Parole boards, at both the state and federal level. Probably a few defense attorneys too. That's a lot of hands to grease for a warden to get some juicy "free" labour.

May as well just hire workers at that point, probably cheaper.