Then how do u maintain your infrastructure?
It's very hard to compete with a service that gives itself away to the consumer for free.
For example, roads are multi-million dollar investments. What kind of person would buy up land for millions and pave roads for millions, when there's a free service with a similar offering throughout the country? He would hardly get any business.
That's why you don't see private roads very often. Although, you still see private toll roads in circumstances where the free market is still so much better than the $0 price road system that it's still profitable to make a private competitor. Imagine how bad the $0 price public system must be for the private toll roads to still be a better deal.
If a person had to pay a private fee for those private roads, we can apply free market economic theory to predict that the typical person would still be paying less than if his money were taken from him by taxation to pay for the project.
You may wonder about circumstances where it's not profitable for someone to invest, for example remote country roads. The reality is that those roads are already privately built, and the government didn't build them anyway. In many countries across the world, people simply clear a dirt road without any investment from the government. In places where traffic demand is more frequent, companies invest in the opportunity to provide infrastructure services.
I think the only legitimate argument against private roads is the reality that they receive some of their value from exclusive land titles, which is a monopoly given by the state. However, because roads exist among other road systems in a vast 2-dimensional grid, there are many possible alternatives in choices, which would make it more like a potential oligopoly. A market oligopoly would still provide better economic outcomes than a monopoly of the state.
Free market capitalism is not a panacea, but it provides empirically better results than other systems. Socialists promise a panacea, but that's how you know they are either lying or they never actually reviewed the evidence. If you look at the evidence, the free market always provides better quality (if necessitated by demand), more quantity (if necessitated by demand), and a lower price in the aggregate.