Well, in a purely capitalist economy, the answer would be property rights, competition, and liability. For example, a road would be owned by someone, and you could sue that someone for damages if the road damaged your car. A road owner could discharge liability risk by purchacing insurance, and insurance underwriters could require some minimum standard of maintenance from owners in exchange.

> You need some kind of government for such things as education, healthcare, roads... fixing potholes...

The whole point of the article that spawned these discussions is that society has already delegated the responsibility for fixing potholes to the government, and the government is doing a crappy enough job of fixing potholes that "art activists" need to make potholes into public art projects to get the government to actually do its job.