There is tons of low-hanging fruit too - it's not like you have to axe safety laws. Stop outlawing taller buildings, parking minimums, let businesses be built near housing, and so on.
Also, people in the U.S. have ridiculously large houses (except in S.F. and New York).
800 square foot is huge, the average 2-bedroom apartment here in Montevideo is about 600 square feet, and serves a family of four more often than not.
http://www.nytimes.com/2016/10/06/style/portland-affordable-...
in Singapore the typical hdb flat for a family is 2-3 br which is between 900 to 1100 sqft (but goes up to 4 brs at 1600 sqft). and on a habitable land basis it is one of the densest cities in the world. so yes you can provide liveable spaces to a lot of people and have them all in the same area at once.
but they also have a state admin that controls a large proportion of residential land supply and is willing to sacrifice property prices as the main method of wealth creation (which imo is a good thing, because firstly one can never fully unlock that kind of equity in his life as long as he needs a place to stay, and second because it pulls capital away from productive sectors)
But they also have laws around cars that would have Americans screaming for their guns. A certificate of entitlement (COE) can cost $50~$70k SD, and that's just for the right to buy a car. That doesn't include the cost of the car or registration.
This is untrue. A reverse-mortgage or HELOC can easily unlock the equity while keeping your ownership stake at a safe level and allowing you to continue residing.
In this way my car would be stored in a secure (either monitored or physical) area outside of the city core.
Given that, it is logical to restrict the use of in-city travel to electric vehicles, bicycles / other human powered devices, and foot traffic. Maybe we could even have nice people mover beltways and fully covered ways between the buildings. (turning the city in to more of a mega 'mall')
(In my (European) city we actually have the opposite - new developments are unlikely to be approved unless they're "zero parking", because we already have as many cars as the streets can take).
Taxpayer owned, profits (after maintenance, expansion of the program, etc) going to decrease taxes, parking structures at the edges of cities located at nexus points of vehicle and intra-city transit grids: preferring density on both.
Step 2:
Make movement /intra/ city on public transit and systems free (possibly only for uses of the parking system).
Step 3:
Affordable 'carts' designed to be used with the transit system for people to move goods from their cars and/or shopping trips back to their homes. Bonus points if there are 'pod' versions that are lockable, trackable (smart phone app), and which other delivery services can be paid to bring to your apartment/condo/etc.
Step 4:
Expand the jurisdiction limits of the city to the point that it encompasses the metro area, to make planning actually work.
Step 5:
Encourage development of the right kind of housing in the right areas; encourage it by carrot and stick until the price of housing is where you desire it.
Of course, the parking lots service ~1000 people, while apartments obeying the height limits might accomodate a few dozen and would of course be even more desirable/expensive now that commuting to the station from far away is harder.