Natural monopolies should always be run by the state.
I think there's some examples of a split model that work well, i.e. the grid is publicly owned but the retail functions such as metering, billing, and service connections are private and have competitive providers.
Consumer choice, or public good/public utility: Choose one.
A deregulated market should provide choice, if it provides monopoly the gov should step in either by breaking up (forcing choice) or making public (forcing good).