Not only is this not possible without probably half a century of building high density housing (and realistically, never, because it would require lots of eminent domain seizures and tons of lawsuits), but it’s also... not really desirable? Half the point of not living in a city is cleaner air, less light and sound pollution, and less people.
Why would a programmer, artist, schoolteacher, hairdresser, restaurant owner need to travel any great distance from their village or town?
Most people in the world already live in cities... and they like them. They like looking at other people, smelling them, ranking and comparing them, copying them. They like the convenience of being able to get around easily, have other people cook food for them or play music for them.
The inevitable and obviously viewable consequence of people moving out of cities is that they create noisy, polluting, long-distance commuting sprawl: exactly the opposite of cleaner air and less light and sound pollution.
In order to move back away from the existing situation of an earth riven by roads the incursion of humans into ever smaller fragments of natural ecosystems we need to reduce the population and concentrate it in cities.
This¹ is mostly concentrating on tropical rainforest destruction but the same is true nearly everywhere: more and more roads are built in order to service human desires (cheap wood, grazing or (in EU and NA) solitude and privacy.
It can't go on.
1. https://e360.yale.edu/features/as_roads_spread_in_tropical_r...
Oh wait! Cities should be sub-terran! Can be built very deep and dense, outside temp is fixed so no heating cost, electricity can be produced by compact nuclear reactors, air/water fully recycled. Only essential/important people will be allowed to go outside, to not pollute the environment. Right?
Absolutely, this is another excellent argument against mindless sprawl.
unfinished concrete Concrete is not an ideal construction material if you are worried about reducing CO2 emissions.
It also follows that intercity travel should be restricted, for the same reasons. Yes, if you want to have a pleasant earth to live on then feckless, wasteful travel should be restricted. This does not have to be done by rules -- simply charging people the full cost of their trip would place it out of their ability.
outside temp is fixed so no heating cost, No, the outside temperature is rising, thanks to the freedom-loving, brave self-expression of car drivers crawling like ants to and from their places of consumption to their places of production.
In case you missed the memo: the party bosses are now the ones selling you the polluted suburban lifestyle while they cycle bicycles around clean, gated, low-traffic, tree-lined communities. So, keep living in the past... after all the future won't hold much for you.
The rest of the circa US$10,000/capita should be garnished by taxation and spent on comprehensive electric bus, light electric rail and long distance train infrastructure.
Neighborhoods need to be quiet, safe, green and relaxing. This cannot happen with personal automobile use.