In the Southeast of America a judge was fairly recently convicted of sending underage boys to a private prison in exchange for kickbacks from that prison. He had been doing it for over a decade. And that’s just one that made the news.
It is obvious that something like this would happen. You cannot create a system with perverse incentives and expect the good faith of those who participate to keep it clean. It is exactly the opposite of the spirit of the American revolution (and the rest of democratic revolutions)
Again, I'm European so I can't be sure about this, but I think some of those issues are worse because of the scale, not the thing itself. The entire healthcare system is private—if all prisons were too, I think that would be much worse than the healthcare situation.
As for politicians, up until this election cycle, they at least had the decency to pretend. From now on, we'll see what happens.