I think one of the issues is that once you start designing places around driving, cars become non-optional for day to day living, whereas many places designed around transit generally do not expect people to use transit for every single outing.

For example: most car oriented American suburbs simply require a car for anything other than visiting a neighbor, whereas in a transit oriented city you might use transit to commute to work, but be able to walk to some local shops and services.

I think many people who are familiar only with car dependent lifestyles make the mistake of imagining a car-free lifestyle that involves replacing all of the car trips they make one-to-one with bus or train trips, which would indeed be really cumbersome, but isn’t really how things work (at least in my experience growing up in a rural small town in the US and having lived in a couple of European cities and NYC).