What exactly would you privatise? (read: hand over obscene profits to a rent-seeking private entity).
Another function of government is, like it or not, in somehow providing legal tender and in the process regulating it. Efficient free markets need fiat medium of exchange, however counterintuitive that might seen. Because otherwise the trading parties would not have any common value reference, and sooner or later the market itself will create something akin to a government and state. Which is well, probably how the idea of governments and states started some thousands of years ago.