If a business fails to perform well, its customers can choose another provider, and the business will have to improve, or else it will fail.

If a government fails, what recourse do its "customers" have? Wait a few years for the next election and hope that the truth about the government's poor performance wins out over the propaganda, and hope that the citizens vote in competent, honest officials, who might gradually make improvements, despite having to work through non-elected officials who are difficult to replace for incompetency? How often does that happen? And what if the officials in question are merely appointed by those who are elected, and thereby insulated from accountability by several levels of indirection? What recourse do the "customers" have then? Can they choose another "rail provider"?

The private sector has natural consequences for failure and a natural incentive to excel and be efficient (certain circumstances, such as monopolies, notwithstanding). The public sector is heavily insulated from consequences for failure and inefficiency.

That doesn't mean that everything should be privatized. It means that we shouldn't be surprised when a service provided by the public sector fails to perform well or efficiently, and we should carefully consider what the government ought to be responsible for. Also, we should make it easier to hold government officials accountable and replace them for incompetence. If someone wants the security of a public sector job, they ought to be held to the highest standards.

Public ventures are like that, but without the bankruptcy.