The government is a representative appointed by the people to represent the people. Hence when the government owns public infrastructure to provide services people's taxes pay for, it does in the best interest of who it represents. The government ensures a high-quality supply that is funded from general revenue. That is why governments collect taxes.
The key point is in who it represents. It is common in present times that the government represents corporations and not the people. Therefore, infrastructure is privatised and there is no regulation to control pricing or standard of service. In such circumstances, the people continue to pay the same taxes and have the additional cost of paying to use the privatised infrastructure. In a capitalist society, corporations are free to use and abuse the system for profit.