I 100% agree in principal, but I think there is something psychological about paying even a small amount of money that makes people treat public transit differently (better) than if it it’s entirely free.
Sort of related, I can think of NYC charging $1 for a subway card, you don’t see discarded subway cards on the floor of the stations.
More people in buses and such, less of them in cars on the street. It's just a good business for any congested city, which is pretty much all of them.