Earlier quoted context omitted.
That's because gas taxes are an unusually live wire in US politics, not because roads are fundamentally uneconomic. Until 2008 gas taxes did cover highway spending, and they now require general transfers because gas taxes weren't indexed to inflation. According to this website the taxes weren't increased since 1993, so in practice the US system has been deliberately starved of sustainable revenue. https://taxpolicyce…
You've now admitted that most of the cost of maintaining and building roads in the US is borne by government subsidies. I just looked up how Germany funds its road network. It turns out that 2/3rds of the funding comes from taxes (subsidies, in other words).[0] 0. https://bmdv.bund.de/DE/Themen/Mobilitaet/Infrastrukturplanu...
Germany spends ~16B EUR per year on roads at the federal level:
https://www.statista.com/statistics/1293915/federal-expendit...
The amount it gets from motor taxes is vastly in excess of that:
https://www.destatis.de/EN/Themes/Society-Environment/Enviro...
That's not surprising because Germany has the highest motor taxes in Europe:
https://www.acea.auto/press-release/motor-vehicle-taxation-b...
The US does subsidize roads but it doesn't have to, hasn't done so in the recent past and arguably shouldn't be doing so.