The fact of the matter is: many people in the US like it how it is, even if we don't.
Edit: If anything we currently have the reverse case, with dense areas where infrastructure is shared by many subsidizing less dense areas where roads and houses serve much fewer people while providing less tax revenue. There have been some good articles on here about this over the years.
Nobody is advocating forcing everyone to live in dense housing. Our current political/legal system massively favors and subsidizes lower density. Removing that favoritism is not unfair at all.
If you don't fund their roads you can't tell them "but you need a sidewalk".
The Americans with Disabilities Act says you need sidewalks.
What's the enforcement mechanism if the entity writing the rules doesn't control the purse strings? Tie them up in court for 10yr and then when you finally win they just do something marginally different to the same end (i.e. exactly what we see with civil liberties).