But the bigger issue with your argument here is that much more of Japanese residential land in major cities is used for multi-family housing than single-family. I'm not saying we should not allow single-family homes to exist. I'm saying zoning currently allocates far too much land exclusively for them. Tokyo is a pretty terrible counter-example for that.
It's the same thing with cars. Nothing wrong with driving, American cities just make them hyper-dominant rather than one option among several.
It doesn't help your argument either when the video itself admits pop growth in Japan is so low that housing isn't considered a good investment.
The average family making average wages in Tokyo, can afford a brand new detached home inside central Tokyo.
The same is not true in any of the top 50 cities in the US. Even the smaller unpopular cities, even the cities that have slower population growth than Tokyo, or have cheaper land than Tokyo.
You should watch the videos linked above, it explains all of this in simple but detailed language.
But in any case, as far as I can see your vision doesn't even conflict with the urbanists. They want the dense urban cores and excellent public transport that allows Tokyo's suburbs to exist. Where they are hostile to suburbs, it's where they are enforced by zoning and are getting in the way of density in places where it makes sense and making single family dwellings more expensive in the process.
Indeed many would argue that the success of cities in Japan can be largely attributed to their laxer zoning laws, which is one of the primary things urbanists argue for.
None of that is actually true. https://www.youtube.com/watch?v=iGbC5j4pG9w and https://www.youtube.com/watch?v=Jv6SbFlZMbU Apartments are great for those who want them, but there's nothing wrong or anti-urban about family housing.
You can easily give everyone (edit: everyone who wants one) their own single-family detached housing (with privacy, and parking), inside a major city, for really cheap. It would still be 100% supportive of walking, biking, and transit, and can scale for at least the next 100 years. I can state this as a simple fact, because it is, it already exists on Earth today.
Wealthier Americans just refuse to let that happen in our own cities. We simply don't build urban housing for families (even in instances where zoning rules do allow it) so families literally can't make that choice. Cities force sprawl, and then complain that decisions must be made to service the sprawl they themselves made.