"A man convinced against his will
Is of the same opinion still."
Your mind is made up, so it's basically useless for me to answer your question. It would be like trying to teach music to a pig: the music teacher gets frustrated, and it only annoys the pig.
Nonetheless, there are many things that government does better than private enterprise.
Adam Smith, the intellectual founder of capitalist economics, discusses several of them in his classic study "The Wealth of Nations," in a section called "The Legitimate Expenses of the Sovereign."
To people who haven't read Adam Smith, let me offer several examples that won't persuade YOU, the author of this question, but might persuade those with open minds:
1. mass transit systems are an example of something that government does, and does moderately well, and that the private sector mostly won't do or can't do at all. Yes, public subways systems and bus systems are imperfect, but when they're operating (which is most of the time) they get millions of commuters in & out of big US cities.
1.5 Government funded highways, rural public roads, and city streets. The provision of public thoroughfares is about 1 million times more efficient than relying on private enterprise to do the job, and less subject to abuse than private turnpike roads.
2. The US national park system -- in terms of preserving bits of nature for humans to gaze at in wonder, and for not too high an admission price -- also is about 1 million times better than anything the private sector has to offer in competition. The government may not be able to build a Disneyworld, but it's miles ahead in terms of preserving the Grand Canyon, Yosemite, Yellowstone National Park, the Great Smoky Mountains, Rock Creek Park in Washington DC, the Everglades, the Grand Tetons, Bryce Canon National Park in Utah, etc. etc.
3. The Internet happens to be an outgrowth of a public-sector effort, original sponsored by the Defense Advanced Projects Agency, or DARPA, to link together US computer systems in a way that could withstand nuclear attack. DARPA did the spade work for what has become the entire world wide web, when the private sector either wouldn't or couldn't.
4. The US Social Security Systerm, for all its faults, still provides a good that almost no private-sector pension fund does anymore: a "defined benefit" retirement program, as opposed to the "defined contribution" systems offered by the private sector. The Social Security system can guarantee you a certain retirement income when you reach 65; your investments on Wall Street, however, may plunge in value and provide you with almost nothing.
5. Police and fire protection services are "collective consumption goods" that almost by definition must be provided by the public sector, not the private sector.
The problem with private police and fire departments is the "free rider" problem: a private fire department needs to charge for its services, and if someone refuses to pay the private company needs to let the person's home burn down -- thus endangering the whole neighborhood. A public, government-provided system for funding "collective consumption goods" is more logical & efficient.
The same logic goes for - say, national defense spending. Much better to have the government do it than to rely on private armies of mercenaries.
6. Well-funded public education can work, and can work at a lower cost than private sector schools. I attended well-funded, well-run public schools from kindergarten through graduate school at the University of Michigan, and they were both high-quality and a lot cheaper than the competition.
7. Environmental regulation: Again, the fact that nature doesn't respect private property lines means that this has to be a "collective consumption good." It doesn't work perfectly. But if we count on competitive capitalist businesses to protect the environment, when many of the benefits won't turn up on the corporations' balance sheets, environmental regulation won't get done at all.