I'm fairly sure it's an equilibrium thing. Like yes, if you suddenly told a bunch of people that they have to use trains for the next year, trains would get more frequent, and things would be better for everyone. However, they likely wouldn't be better enough to completely sway everyone, so after the year ends a bunch of people would switch back, trains would get more infrequent, therefore more inconvenient, others would switch back again, and you'd end up in the same spot. People who used trains before would think that one year was the shit, but everyone who opted out would cite the inconvenience even during that year of heightened frequency. (It would take a while to settle back though.)

Whether it's this or a spiral depends on the magnitude of the change the popularity of trains would have on the experience of using trains. And the thing is, increased frequency still doesn't solve all the gripes, so I don't see it spiraling anytime soon.

For example, for my commute, I time it so that I leave the house at the exact right moment so I only have to wait 1-2 minutes at the station, a necessary buffer to account for imprecision both on the train's part and on mine. On the return trip, I leave mostly randomly but trains are more frequent at that specific part of the day, so I have to wait about 6 minutes on average. Waiting accounts for about 8 minutes on average out of, let's be generous, my daily total 110 minute commute.

The daily total by car would be 60 minutes. It would be free of annoying people who listen to music without earbuds, smoke in crowded places (and often around the only entrances/exits!), and push you around on a crowded train. It would have significantly lower exposure to adverse weather, require less physical exertion, and it would be free of the stress of being on time or paying for it with sometimes 15-20 minutes of your life. I don't know how you can fix any of that with better public transport.

With all that said I do still use public transport, but I totally understand anyone who doesn't. If you can replicate the convenience of cars with public transport without requiring everyone to live exclusively in large cities, I'm all ears, but until then, I don't think you'll be able to fully eradicate car culture. And that does come with the recognition that cars are way more popular nowadays than they have any right to be, often due to shitty zoning and city design, but there's a lot you just can't do with public transport.