This is just a big network affect failure. A bunch of zealots starting a cult in the desert isn't a city, and fails quickly every time.
> there is no blanket "striking the root" answer here
I didn't invent this. This is how the whole world worked, in general, 100 years ago. Japan already went back to this 30 years ago, and it absolutely worked.
> denser buildings now mean more traffic
But less need for cars when you can walk to where you are going. Also, public transit becomes a viable option at higher densities.
> existing properties lose access to sunlight
Exactly the NIMBY attitude that supposes you get to say what other people do with their property. This is what makes homes unaffordable, neighborhoods unwalkable, our working days full of commute time, the atmosphere full of CO2 and soot, and consolidates all sorts of commerce from the small and local into the national and international mega-corps. Great tradeoff!