More to the point, here's where this argument breaks down:
> If a city is not overbuilt and overpopulated to the point where the road infrastructure is overwhelmed
Given current demographic trends within the United States, major cities are guaranteed to see population growth beyond what current American public infrastructure can sustain.
Compounding this problem is the fact that there's significant overlap between the segment of the population which thinks that driving is a sacred right and folks who think that spending public money on efficient public transit is unacceptable.
I enjoy driving. It doesn't work for major cities. And those same cities are inevitably going to get denser if trends continue. Everyone driving his or her own car to their job (or to "the things they want to do") in the name of personal convenience is not the answer.
Not speaking for parent but the typical response would be "but then people should stop moving there", to which I reply that any utopia can sound good if you disregard people's incentives, desires and needs. Let me try: communism is in fact great, it's just that every time the people at the top end up corrupt for unrelated reasons.
Those costs are paid for by destinations, as road tolls are limited in the US. At a certain point, and the evidence strongly suggests many parts of the US are past this point, you’re spending more money on road maintenance, than you’re collecting in tax from destinations.
No amount of “cars are more convenient” will change the simple economics that cars and their infrastructure are vastly more expensive than either public transport, or bike infrastructure. And based on the atrocious conditions of US roads, it seems the US can’t afford it’s car infrastructure anymore.