Well this is conversation is about libertarians, not "right-libertarians", I am more of Geo-Libertarian

>>Something's got to compel landowners to give unfettered access to their property to run wires and pipes to other properties

Yes it is called a voluntary agreement built into the title of the property (aka convents) normally when a subdivision of land is created, where by utility paths laid out by the developer. Subsequent purchasers of the land must agree to these convents, including utility easements, when they buy the property.

government is not required for that.