[bluGill]

Only if the trains are given enough budget that there is a train every 5 minutes (or less) at every station, the train routes provide reasonable ability to get anywhere, and the trains run "fast".

No train system in the world has all of that, which in turn means they need more money and so free riders harm the system's ability to get people where they want to go.

[aziaziazi]

I think gp point was that making it mandatory (or tax) would increase the budget of Deutsche Bahn.

[bluGill]

Maybe, but I've never seen anyone with such a proposal serious about giving enough money to run great transit everywhere.

By everywhere I include farms in the middle of nowhere as that farmer has a relative somewhere who wants to visit and the lack of great transit pushes that person to a car and then opposing transit subsidies. By getting some money from riders there is at least some inventive to make good compromises.