In many places, it's not.cits a lifestyle problem where people value their own perceived convenience without considering any externalities.
I live in a small (500k people) city, where the school you go to depends on what part of town you live in. Each school has probably less than a half mile's radius. Yet despite this, a large number of people still drive their kids to school.
People don't use trains because "they're expensive, and I might need to leave 8 minutes early or later some day", despite not considering the cost of fuel, parking in a city centre for a day, and maintenance of their car. They don't use buses because they're "inconvenient" despite tge fact a months bus pass in my city is cheaper than 2 days parking in the city, and all the major artery routes are served at 5-10 minute intervals during peak hours.
People living in these kinds of situations won't change unless they're forced to
That's an unfortunate side-effect of trains having timetables. When a train is 5 minutes late, it's really frustrating because a) you don't have any agency, b) you usually cannot see anything related to the reason for the delay, and c) the idle waiting makes the time feel longer.
When a car is stuck in traffic for 30 minutes, it doesn't feel like you're losing 30 minutes. It just feels like a force of nature happening to you, and also it feels shorter than waiting for a train for 30 minutes because you're still engaged in the act of driving. You still have some agency because you have the choice of trying to change to that other lane that always feels like it's moving faster.