>Why the assumption the government has to be inefficient.
>Get the right managers in and give them the right authority and there is no reason it shouldn't be run efficiently.

Because there is no profit motive for the government. Companies have to be efficient to survive in capitalist markets because there is always competition right around the corner. When the government provide a service they have no profit motive and naturally descend into inefficiency. If government was capable and efficient, then Socialist countries would rule the world. They don't.