There's a lot of information... Strong Towns wrote several articles and a book on this, then this youtube channel tried to summarize the important findings into

There's a lot of information... Strong Towns wrote several articles and a book on this, then this youtube channel tried to summarize the important findings into a 7 part series. The gist is this: - US-style car-centric design has created cities filled with parking lots, wide roads, sprawling low-density development, and as a result also sprawling water/sewage infrastructure - High-density downtown neighborhoods produce much more revenue per acre than low-density car-centric neighborhoods. The higher revenue is more than sufficient to fund yearly maintenance as well as pay off the replacement cost of infrastructure (whereas the low-density, low revenue areas can't fund the replacement cost so need to be subsidized by downtown) - New neighborhoods enjoy their federally-subsidized new infrastructure as they don't need to concern themselves with replacement cost for decades. - But when it comes time to replace the infrastructure, these low-density areas cannot fund the replacement (e.g. Backus, Minnesota has very low density and sprawling sewage infrastructure; replacement cost would be $27k per resident, which is greater than their average income). So they go into debt - The piling debt is obviously unsustainable. e.g. Tampa, Florida needs $3.2bn to replace its water infrastructure. It already spends more money each year to service the debt it has borrowed for its water infrastructure than it spends on actually maintaining it. - Some cities are lucky - they have a growing population so can kick the problem down the road by using new tax revenue from new developments (remember, yearly maintenance cost of new infrastructure is very low, so new developments are net tax positive as long as you pretend like you never have to replace the infrastructure). This is the growth ponzi scheme. tl;dr Only high density downtown areas are able to simultaneously fund their infrastructure maintenance cost as well as the replacement cost over decades; lower density areas outside downtown depend on downtown's excess tax revenue to fund their replacement cost. But some cities just depend on ever-growing urban sprawl to use the new tax revenue to fund their growing debt and aging infrastructure These are all high-level ideas and conclusions, which is why Strong Towns' publications are so important. They investigate tons of actual cities and towns across America and show you actual numbers.