The key point here (and biggest advantage of Japanese cities) is that nearly every building is mixed-use by default, regardless of local density levels. This post does a great job illustrating the difference this makes: https://urbankchoze.blogspot.com/2014/04/japanese-zoning.htm...
For comparison, even our best-case scenarios for urbanism here in the states (like NYC) have incredibly convoluted zoning rules, which in turn make it impossible to build anything new without intervention from the city/state: https://zola.planninglabs.nyc/about#9.72/40.7125/-73.733
> The key point here (and biggest advantage of Japanese cities) is that nearly every building is mixed-use by default,
Also, Japan generally has good mass transit throughout their cities, which essentially doesn't exist in the US. Less mass transit -> more cars -> need for parking -> larger buildings with setbacks to include parking -> less density -> less mass transit... Land use and transportation systems in the US have been co-evolved to the present sub-optimal state we have now.
It’s not that simple. My city in Silicon Valley foists mixed use on most new developments in the form of ground floor retail. Yet it’s often vacant.
The best videos on this (in my opinion) which compliment urbankchoze's post:
‣ Not Just Bikes: https://youtu.be/jlwQ2Y4By0U
‣ Life Where I'm from: https://youtu.be/wfm2xCKOCNk