This is just rehashing pop-urban planning buzzwords. Like I'm not sure where the trend of just handwaving every problem as easily solvable by "rail! Shinkansen! City public transit even out of cities!" came from but it particularly does not make sense in this situation considering the commenter you replied to specified he talked about spread out, smaller cities with frequent stops. Which is the opposite of what the shinkansen is for.
Have you ever tried taking these lines before? They have high speed rail between big cities, and tons and tons of small branch/feeder routes out to small towns with the most frequent stops ever imaginable. Getting from huge Tokyo to small Gifu actually works.
It did take some planning however. The USA's model of just "build that office complex wherever you want!" wouldn't work.
Which is exactly my point! That's already the current situation on the ground in the USA. So yes, it wouldn't work there. Unless you'd literally move around millions of jobs, offices etc which is absolutely not feasible. Trying to build public transit around that structure just to fit an idealized vision of somewhere else is weird. Japan built the system that fit their needs and their situation and the USA should do the same.
They did this for a variety of reasons some noble (grand visions of urban renewal based on cars instead of public transit) and some odious (breaking up non-machine voting wards, enforcing de facto redlining post the Supreme Court decisions, etc). They were able to make sections of the city, specifically the near south and south west places you commuted through instead of to. Similar things were done with tearing out el tracks, trolleys and the removal of commuter rail from further south neighborhoods that had been alternate business districts to the loop. These were conscious urban planning decisions to reinforce the pattern of outward/in commutes.
American Pharoah is a not particularly good biography of Richard Daley that happens to include a good book on Chicago urban planning in the late 40s to late 60s era.
This problem has been solved for awhile now, at least since the 1960s when the first intra-city/province shinkansen came online. Just because some other countries suck as badly as the USA at it doesn't mean it is an unsolved problem.