> Private cartels are just bad governments with even less accountability or incentive to be efficient.

It's kind of six of one, half a dozen of the other. You can't vote out a monopolist, but unless there is a law against competing with them, there is a threshold for how bad they can get before somebody actually does. The problem is that threshold can be way past the point of anywhere you want to be.

Whereas governments can get even worse because if you resist their unreasonableness they declare you a criminal and resort to violence and you can't go to the police because they are the police. Voting can mitigate this, but there are governments without democracy, democratic governments that are structurally insulated from accountability in practice (see US incumbency rate and Congress abdicating its role to unelected regulatory bureaucrats), and even in a pure direct democracy you still have two wolves and a sheep voting on what's for dinner.

What you want is neither of these things.