The free market is not a panacea. It does not eliminate old age, and it won't guarantee you a date for Saturday night. Private enterprise is fully capable of awful screwups. Both theory and practice indicate that its screwups are less pervasive and more easily corrected than those of government enterprises.It's from an article on externalities, written by Gene Callahan.
Libertarianism, particularly in its support of the free market, is not at all utopian. We realize that there is no perfect answer to the problems facing society. We just understand and accept that private solutions always work better than government coercion.