Regarding your other point about shades of classism behind liberal hopes for urbanization, I neither know nor care. My (much) earlier point about the unsustainability of low-density residential mostly concerned the car-centric suburban lifestyle crossed with a ream of exceptional infrastructure planning blunders that has left most US counties, and even most major cities, saddled with an infrastructure they cannot afford to maintain. In some extreme cases, infrastructure maintenance costs exceed the entire gross product of the municipality.
The US developed its infrastructure knowing they couldn't afford to maintain it, under the assumption that they'd grow themselves out of the problem. Well, the US stopped taking immigrants and white people stopped ****ing, so that isn't gonna happen now, is it? That means **** is going to fall apart, cities are going to retreat away from the suburbs, and services for surrounding rural areas are going to decrease. Because they, logically, have to. There is no other option. The US has neither the money, nor the resources, nor the manpower to maintain this infrastructure. It's going to degrade, it's going to fall apart, and it's not going to get replaced. You can live in the jungle if you want, but shooting the messenger isn't going to change the fact that it's going to be a jungle.
"It's so weird that Flint doesn't have safe drinking water yet. You'd think they'd have done something by now."
"That's strange, NBC just said a third of Puerto Rico still has no power. It's been 7 months."
"Rome sure hasn't paved that road in an awfully long while. I hope the empire's doing alright."