I'm also inclined to argue that government run monopolies are all inefficient, but to different extents, and so using them to estimate costs is highly questionable.

This is getting into politics, but...

There have been many empirical studies examining the efficiency of government bureaucracies versus business in a variety of areas, including refuse collection, electrical utilities, public transportation, water supply systems, and hospital administration. The findings have been mixed. Some studies of electric utilities have found that publicly owned ones were more efficient and charged lower prices than privately owned utilities. Several other studies found the opposite, and yet others found no significant differences. Studies of other services produced similar kinds of mixed results. Charles Goodsell is a professor of Public Administration and Public Affairs at Virginia Polytechnic Institute and State University who has spent much of his life studying bureaucracy. After examining these efficiency studies, he concluded: “In short, there is much evidence that is ambivalent. The assumption that business always does better than government is not upheld. … When you add up all these study results, the basis for the mantra that business is always better evaporates.”

Source.