Most people in the world grow up in a country that is fraction of the size of America, and developed in the era of history before cars. If a city developed and grew in the Middle Ages, it is going to be a tightly organized place, so people can get to other parts of the city by walking or horse draw transportation.
But America had most of its development during the car era, and cities adopted a larger sprawl, even creating suburbs, from which people could drive.
Now that we're built up this way, with lots of suburbs, it's common for people to live 30-60 minutes, by car, to their workplace. Stores restaurants, schools, etc., are all too far to walk, or even bike, and the route may be dangerous due to traffic. Cars are essential to live a normal life.
There is an effort to upgrade public transportation, but things like trains are always going to be better within the cities. Traveling between cities is just too far, and even current trains aren't sufficient. It literally takes the same time to drive, and is probably going to be less expensive than a train ticket. If we had maglev bullet trains it would be faster, but the price would also be much higher.
We've already developed as a car society, and our geographic size makes trains and busses problematic anyway. We can try to add bullet trains, and a other efforts to relieve traffic, but we will probably always be a car culture in America.