Never believe a marketer telling you that you NEED marketing. Life will go on even with very limited marketing. You and your neighbors do not need it. Capitalism does not fall apart if it gets more expensive to force someone to learn about your product when they do not want to.
1. All cars have a configurable display that shows text. It is constantly scrolling through boilerplate that is not conceivably helpful to anyone, like "Don't spend too much time looking at your phone". But if you watch it for a minute or two, eventually it will briefly display the name of the next stop before going back to the boilerplate.
2. Some cars, but not all cars, have a stylized layout of the subway line embedded over the windows. There are lights running between the stops, and those lights are red if that part of the track has already been covered and green if it hasn't been. The part of the track where the train is currently located, and the upcoming stop, have some other status, which I think is an unobtrusive flashing.
The fact that this map display cannot show any information other than the current location of the car means that it shows this information at all times, making it millions of times more useful than the configurable text display that all cars have and fail to use appropriately.
But there are no ads either way. There's just the good system and the terrible system. I would argue that software to control this kind of display is a fundamentally misguided endeavor - the more controllable it is, the worse the user experience will be, because the people controlling the display are not interested in the user experience.