Gas Stations pay for themselves. Otherwise its also tax based.
Still completely free public transport is not a good idea instead of investing in a high quality offering. (Higher Frequencies, Better Vehicles, more dense network).
Because People usually take the car because it is more convenient, its always more expensive than public transport.
And in the past, free offerings have just diminished people walking or taking the bicycle, but no shift Car>Public Transit
This is only part of the equation, unfortunately - free transit that is of significantly worse in terms of travel time/reliability/accessibility/comfort won't get used at significantly higher rates.
This is why some transit advocates consider free transit to be an inferior use of funds when compared to investments in the system as a whole, which I think is a fair point.
I'd of course like to see both, as ticketing systems contribute negatively to the overall quality of the system (paying for tickets/passing through ticket gates slows down the system, ticket checkers represent an unpleasant ritual in the system).
I lived there to go to university at the beginning of the year. It was crazy to have my free card, the administration was so nice.
Montpellier is not perfect but they are trying and are in the process of succeeding. Urbanization is top notch with many green public spaces, libraries, and everything is cyclable.
They also cracked down on cars in the city center. No wonder why Montpellier is one of the best city to live in / study.