Free public transport means worse service. In the long term, subsidies < subsidies + fares, so there would be less money to fund the operations. At the same tim

Free public transport means worse service. In the long term, subsidies < subsidies + fares, so there would be less money to fund the operations. At the same time, many people who would otherwise walk/cycle or not take the trip at all would be using public transport, and the reduced service would be crowded. Because the quality of public transport would be low, people who can afford it would prefer driving. That in turn would lower the subsidies, because people are always looking for ways to lower taxes and reduce public spending in services they don't need. Sometimes the fares are also higher than costs to discourage using public transport, because capacity is limited and increasing it is effectively impossible. London zone 1 is a good example of this. People who won't use public transport will walk/cycle or not take the trip at all. They won't switch to driving in any significant numbers, because that would be physically impossible.