Exactly. It was the "extensive local rail and other transit network" that made public transport magical when I visited. I was based in Kyoto, but we could "pop into" Osaka. Blew my mind.

Yup. Only times I used taxi or ridesharing in Japan was when I flew in with elderly relatives, and taking Uber to the hotel made far more sense than trying to herd 6 people and their luggage through several train changes, and when we were stuck on Mt. Fuji because the kid decided to try hiking to the top, forgot to turn on his phone, and we missed the last bus back (pro-tip 1: calling a taxi to the half-way station on Mt. Fuji and going to the nearest train station is bloody expensive; pro-tip 2: even in a middle of summer, once the sun sets it's bloody cold up there).

Other than that, getting anywhere using transit worked great; but the Shinkansen is a very small piece of the puzzle.

A problem not compared here is that in most of the rest of the world public transit is actually predominately used by those with money, not those who "can't afford a car". In the US public transit is where someone is more likely to find homeless, drunk, unwashed, or otherwise uncouthly scented (smoking, perfumes, body-spray, etc) individuals and tight seating that forces undesired social interactions.

Public infrastructure of all sorts, quality, quantity, and affordability of housing, healthcare, and handling the social issues of the less fortunate are all different facets of larger issues in the US. Addressing them properly requires a comprehensive, national-scope of effort (but with local tweaks), approach that would eliminate or consolidate the right parts of red tape, incentivize desired results across large geographic regions. It would need to steamroller over entrenched local politicians, NIMBY housing owners who want a magic wand to freeze time at the highlight of their lives (cost to anyone else be ignored), and transcend both gerrymandered political areas and voters with too little time, education, and wisdom to start on the enlightened path.

However, it is also about culture. The American Dream, one of prosperity for all, is at odds with the other american dream, "making it big". A pipedream usually enabled mostly by having the right social connections thanks to rich parents and a private safety net that allows taking big risks until one pays off.

People with money use transit in NY or Chicago, too, because it works (more or less) and is sufficiently convenient. But in both places you can use transit to get reasonably close to where you're going. When I lived in SV, it was theoretically possible to get from my home in San Jose to office in Sunnyvale, but it involved either getting up at some ungodly hour to maybe, possibly find parking at Caltrain stop, or spending few hours on buses.

Building CHSR alone will price out people who live close enough to train stations, but without all the supporting infrastructure it is very unlikely to actually do anything for the housing crisis.

Light rail (including subways) already have. These solutions all suffer most of the same problems and it really doesn't matter which one succeeds, as long as they aren't part of a fantasy about revenue expectations. Over time, they pay for themselves...until the corruption sets in.