Admittedly, I'm one of those office workers, so I haven't used transit much since the pandemic began, but I'll be back to using it daily early next year or so (subject to change, as always...)

It's always going to depend on your line and your time of day for how pleasant transit is, but as a general rule the more families use a transit line, the nicer it is. When I lived in Brookline, MA and took the Green Line trolley, it was extremely pleasant, even during non-work hours (when you would see parents with small children and such on your ride). However, the line goes through an upper middle class semi-dense[0] suburban neighborhood, so of course it was nice.

The same logic applies to Tokyo. The entire city is dense and almost every person takes transit sometimes. Even if there are unpleasant people (I'm sure there are), the overwhelming number of ordinary families, office workers, and so on, taking transit makes the less savory riders nearly invisible, at least to tourists.

This is why I say it's a chicken and egg problem: you won't ever have nice transit unless you have a system where middle class people want to ride transit, and you won't have that system unless it's more convenient than driving the car, and you won't have THAT system unless housing is dense.

> I do not want denser housing.

That's perfectly fair, and I agree that many people feel this way. Personally, I want to live in a city and I like having a lot of neighbors. When I walked through Japanese suburbs (where houses fill up an entire tiny lot with almost no space between them), it felt very at-home to me. But that's personal preference.

> Do you realize how miserable subway stations in east coast cities can get when the AC is broken? If they even have AC?

Yes of course, one of the advantages of taking a car is that you have your own personal climate controlled box with your music and nobody else's noises or smells. I don't dispute this, but that's not really a USA-centric problem (aside from the occasional broken AC in summer or broken heating in winter). Having your own personal climate box will always be more pleasant.

[0] My definition: semi-dense because it felt urban near the main street/transit but in a few pockets of Brookline, you could be a 10 minute walk from transit but surrounded by expensive single family homes on large lots.