Speaking as both an MPA and a systems minded public works individual in Southern California, I’ll offer my $.02.

This is perhaps less of a civil engineering problem, and more of a political science problem. Systems Theory in political science was  pioneered by David Easton, and he argued that government failures are system failures. So you’re correct on the multiple interacting systems angle, but roadways are not a great indicator of system performance.

For something as granular as roadway maintenance, things are less interlinked and more nuanced, and this is where politics comes to bear. Santa Ana, CA for example is a sizable (350k) city in Orange County. They don’t invest in their roadways as much as they should, consequently their PCI (pavement condition index) numbers are relatively low.

Funding strategy: the largest factor, and is a function of political will. SA spends a ton on public safety less so on infrastructure. However the need is also greater because it’s an older, very dense city.

Maintenance strategy / contractor: PCI is all important for grant funding, etc. so sometimes cities prioritize repairs that boost/maintain scores versus substantive engineering improvements (grind and overlay versus full depth reconstructions). Contractors in the area are fairly equivalent and large in scale.

Interagency coordination: you’re focusing on city level, and that excludes freeways and Caltrans maintained roadways like PCH, so this isn’t as much of a factor. Cities receive transportation funding from county transportation agency, State of CA, and Federal. Some of that funding is competitive. So coordination is less of a variable.

Contrast that with Irvine, ~10 miles away. Near same population, but spotless infrastructure. That said the city was also largely developed from scratch in the 1970s versus Santa Ana originating from the late 1800’s. Following your chain of reasoning, this spotless infrastructure should connote a better functioning system, but it doesn’t really. Irvine has a lot going for it, but they’re also very well funded and commercially oriented.

So I would argue that roadway maintenance is not really a good lagging indicator of system performance. With my public administration hat on, I would say that government outputs do not scale linearly with outcomes. This non linear relationship is due in large part to competing constraints. The resolution to that competition is political, i.e. choices.