Trains and short range motor bikes or human powered bikes can definitely replace cars. The problem is the city needs to be designed for it. It can’t replace it in most places in the US because all infrastructure has been biased towards cars for more than 100 years. But if you imagine a city built from the ground up with trains and bikes in mind it is completely doable.
It’s going to take another century to undo the car centric society we have built in the US.