Don’t discount the many sources of funding in America. The state and federal governments can and do pay for infrastructure, along with long term bonds paid using sales and other taxes. The suburbs benefit from the highways to the suburbs, but the suburbs don’t fund them.
https://www.crcsi.com.au/assets/Resources/b6e1625f-d90b-433d...
Orders of magnitude may be hyperbolic, but costs alone are twice as much from that study. Note that some of those costs are directly paid by households and not through taxes. For example, you need a car and drive further distances increasing fuel and maintenance costs.
As one example, muni costs money and sf pays more for BART than WC does. These are still cheaper and more environmentally efficient than everyone owning cars.
2. Bart and muni are not the majority of the $9000 difference. The majority of the cost is various social services. The actual cost of muni per sf resident is something like $500, which is still significant (muni is not a great rapid transit system), but that's far less than the cost of carbon offsets for every resident.
Sure, if you can afford to build yourself a self sufficient off grid home, you may perceive it as more efficient in day to day costs.