There is, and will always be, a role for government as the protector of the less powerful. The Libertarian suggestion that government is dispensible breeds cynicism which breeds complacency. The result of this complacency is that the public fails to take an active role in its own governance and that governance is co-opted by the wealthy and the powerful. In my opinion, Libertarianism greatly contributes to those facets of government it professes to most strongly abhor. There are many important social changes it is simply not capable of.
Market forces exist.
They possess no more wisdom or virtue than the force of gravity. Be assured, the rich and powerful do not abdicate this role. This is not to suggest that government is not often wrong, inefficient or corrupt or that there should not be bounds on the size and powers of government. It is merely a warning that contempt of government is NOT a trait conducive to wise or just governance.