Of course taxes can be onerous, even tyrannical. But as long as people have a say in how their tax money is spent, taxes are a good idea. Something like a highway would not be built without it. As evidence, the first highway system were the Roman roads. The trade and connections they brought led to a massive increase in the standard of living and helped usher in the Pax Romana.
A private road network would require tolls at whatever rate the owner can extract. It could also require that you be a certain religion, or any other criteria. It would also not go far. In a society without government, power would be extremely localized and no one could oversee a project over hundreds of miles. .....
Actually, widespread networks and computers, coupled with micropayments, at least technically is enabling for numerous prior "government functions" to be taken over by the private sector.
The reason is that economically, what you state as the advantage of funding through taxation is actually only funding through a method that collects small amounts from everyone. And it is impractical to place someone in a toll booth position to collect 1/10 cent every time someone uses a section of a public road, because the costs of the toll booth operators would be in excess of the monies collected. Hence, taxes for supposed social goods.
