Humanity stands on the brink of self-destruction because we have yet to overcome the primitive, selfish aspects of our nature. I have to believe that any civilization advanced enough for interstellar travel—without having destroyed itself along the way—must have achieved a certain level of cooperative enlightenment.
Even where there is viable public transport, there’s a stigma against using it. The city I live in has a decent and cheap Metro system. It’s reasonably clean, mostly runs on time, and you only have to deal with the occasional crazy. I took it for a summer after a car got totaled and it was fine.
Yet I work with a bunch of impoverished young people who spend $30-$40 on Ubers every day getting to work. I’ve suggested taking the bus to many of them, there’s even a stop right outside our workplace, and they are always dismissive and disgusted by the idea.