The proper role of government is to maintain law and order, define property rights, adjudicate disputes about rule interpretation, and allow modification of those rights and rules. It should also enforce contracts, promote competition, provide a monetary framework, counter technical monopolies and neighbourhood effects where appropriate, and supplement private protection of the irresponsible.
Possible market solutions are preferable because the governmental process of compromise more poorly represents individuals. Where one can engage voluntarily in exchange, they have a voice. A small enough group has no such standing in the rule of the majority or even in parliaments with proportional representations where a universal outcome is required.