My experience with government-controlled entities is that they become unwieldy and uneconomic behemoths over time that often employ workers (for lower salaries) that can't get employed in the private sector. Yet, we also see private entities milking profit as much as possible.
In some instances, private companies outcompete the public ones, in other instances, it is the other way around (schooling in the US was under discussion here yesterday). Not sure how one would ensure a utility gives the best service at the lowest price. Maybe having different entities (both private profit-oriented and public service-oriented) compete for the same customers?
In my country, South Africa, many decades ago the government created the state-owned electricity provider currently known as Eskom. In the beginning it created cheap and reliable power driving industrial growth, even exporting power to neighboring countries. But it had a monopoly on providing power, and under the disastrous ANC management it was captured and milked dry by state capturers - now it is an unreliable supply, with scheduled "load shedding" black-outs and steep price hikes each year. Thanks to the advances in PV tech, a lot of electricity is now being generated on-prem by homeowners and businesses. There are a couple of very funny (ironic) inconsistencies, like office blocks being 100% off-grid still required to buy electricity (which is then used for something trivial e.g. landscape lighting), and small municipalities that generate 100% of their own power via an investment in PV, still being required to adhere to the official load-shedding schedule and switch off the supply to their consumers even if they have the watt hours at hand and would need to dump them otherwise.