Just responding to the "Why shouldn't governments" argument, but the obvious counter-response to that is that (at least in its current iteration) the government is pretty bad on slapping its own hand. We see this at the heart of the criminal justice system, and we see its ill effects. That is slowly starting to change, and I think for the better, but it's still pretty bad.
In competitive space, what do we do when the government fails to check itself against anti-competitive behavior?
Why shouldn't governments own private industry if it still competes through the market?